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Title: The North American Slime-Moulds

A Descriptive List of All Species of Myxomycetes Hitherto Reported from the Continent of North America, with Notes on Some Extra-Limital Species

Author: Thomas H. (Thomas Huston) MacBride

Release Date: January 27, 2010 [eBook #31098]

Language: English

Character set encoding: ISO-8859-1

***START OF THE PROJECT GUTENBERG EBOOK THE NORTH AMERICAN SLIME-MOULDS***

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  Physarum notabile
(Enlarged one half)
In the field; sporangia in varied magnification, due to inequality in background.

"Diese Kinder der Natur, welche aus einer ungeformten Gallert, und einem unsichtbaren Saamen entstehen, sind im stande, in dem sie sich nach und nach entwickeln und ihre scheinbar nachlässige Bildung genau beobachten (lassen), eben so sehr als die schönste Pflanze, einem empfindenden Herzen die tiefe Achtung und das paradiesische Vernügen zu verschaffen, welches einzig die Betrachtung der Heere der Natur und ihre gleichbleibende Erhaltung durch eine ewige Kraft hervorbringen kann."

A. J. G. C. Batsch 1783.

TABLE OF CONTENTS

CORRIGENDA

The indulgent student will please notice the following for the new edition North American Slime Moulds—

[Pg ix]

PREFACE TO THE FIRST EDITION[1]

The present work has grown out of a monograph entitled Myxomycetes of Eastern Iowa, published by the present author about eight years ago. The original work was intended chiefly for the use of the author's own pupils; but interest in the subject proved much wider than had been supposed, and a rather large edition of that little work was speedily exhausted. At that time literature on the subject in question—literature accessible to English readers—was scant indeed. Cooke's translation of Rostafinski, in so far as concerned the species of Great Britain, was practically all there was to be consulted in English.

In 1892 appeared in London Massee's Monograph of the Myxogastres, and two years later in the same world's centre the trustees of the British Museum brought out Lister's Mycetozoa. Although these two English works both claim revision of the entire group under discussion, the latter paying special attention to American forms, nevertheless there still seems place for a less pretentious volume which for American students shall present succinct descriptions of North American species only. The material basis of the present work consists of collections now in the herbarium of the State University of Iowa. In accumulating the material the author has had the generous assistance of botanists in all parts of the country, from Alaska to Panama, and the geographical distribution is in most cases authenticated by specimens from the localities named. The descriptions, in case of species represented in Europe, are based upon those of European authors; for forms first described in this country, the original descriptions have been consulted. A bibliography follows this preface.

In reference to the omnipresent vexed question of nomenclature, a word is perhaps necessary. De Candolle's rule, "The first authentic specific name published under the genus in which the species now[Pg x] stands," may be true philosophy, but it is certainly an open question how that rule shall be applied. If an author recognized and defined a given species in times past, and, in accordance with views then held, assigned the species to a particular genus, common honesty, it would seem, would require that his work be recognized. To assume that any later writer who may choose to set to familiar genera limits unknown before shall thereby be empowered to write all species so displaced his own, as if, forsooth, now for the first time in the history of science published or described, is not only absolutely and inexcusably misleading, but actually increases by just so much the amount of débris with which the taxonomy of the subject is already cumbered.

In face of a work so painstaking and voluminous as that of Rostafinski, and in view of the almost universal confusion that preceded him, it would seem idle to change for reasons purely technical the nomenclature which the Polish author has established. Especially is this true in the case of organisms so very perishable and fragile as those now in question where comparative revision is apt to result in uncertainty. We had preferred to leave the Rostafinskian, i. e. the heretofore current nomenclature, untouched; but since other writers have preferred to do otherwise, we are compelled to recognize the resultant confusion.

Slime-moulds have long attracted the attention of the student of nature. For nearly two hundred years they find place more or less definite in botanical literature. Micheli, 1729, figures a number of them, some so accurately that the identity of the species is hardly to be questioned. Other early writers are Buxbaum and Dillenius. But the great names before Rostafinski are Schrader, Persoon, and Fries. Schrader's judgment was especially clear. In his Nova Genera, 1797, he recognizes plainly the difference between slime-moulds and everything else that passed by the name of fungus, and proposed that they should be set off in a family by themselves,[2] but he suggested no definite name. Nees (C. G.) also made the same observation in 1817, and proposed the name Ærogastres; but he cites as type of his ærogastres, Eurotium, and includes so many[Pg xi] fungi, that it seems unsafe now to approve his nomenclature. Schrader also has left an excellent account of the cribrarias, the basis of all that has since been attempted in that genus.

Persoon, in his Synopsis, 1801, attempts a review of all the fungi known up to that time. His notes and synonymy are invaluable, enabling us to understand the references of many of the earlier authors where these had otherwise been indefinite if not unintelligible. He makes a great many changes in nomenclature, and excuses himself on the ground that he follows, in this particular, illustrious examples! Unfortunately, so do we all!

Fries, in his Systema Mycologicum, 1829, summed up in most wonderful way the work of all his predecessors and the mycologic science of his time. In reading Fries the modern student hardly knows which most to admire, the author's far-reaching, patient research, the singular acumen of his taxonomic instinct, the graceful exactness of the Latin in which his conclusions are expressed, or the delicate courtesy with which he touches the work even the most primitive, of those his predecessors or contemporaries. Nevertheless in our particular group even the determinations of Fries are not conclusive. He himself often confesses as much. The microscopic technique of that day did not yield the data needful for minute comparison among these most delicate forms.

It remained for DeBary and Rostafinski to introduce a new factor into the description of species, and by spore-measurement and the delineation of microscopic detail to supply an element of definiteness which has no parallel in the work of any earlier student of this group. Under these conditions the revision undertaken by Rostafinski was of a most heroic sort. His work was almost a new beginning; and while in nomenclature he was inclined to follow the Paris Code, yet the inadequacy of the earlier descriptions often made such a course impracticable. The synonymy of Rostafinski is largely that of Fries, and upon this the Polish author attempts to apply the law of priority. In the historical note, wzmianka historyczna, accompanying the description of each specific form, he generally states the reason for the nomenclature he adopts, whether selected from the mass of supposed synonymy or introduced by himself de novo. Unfortunately,[Pg xii] Rostafinski is sometimes purely arbitrary in his selections. He sometimes changes a specific or even generic name, otherwise correctly applied, simply because in primary etymological significance the name seems to him inappropriate. In such cases it is proper to restore the earlier name. Nevertheless Rostafinski is still our most trustworthy guide.

Of course, where later investigations have served to obliterate the once-thought patent distinctions between supposed genera or species, it is proper to unite such forms under the older determinable titles and this we have attempted. But wherever in the present work a name has been changed, the name of the earlier author will be found in parenthesis, followed immediately by that of him who made the change, and in general, recent practice, especially as expressed in the rules of the various codes, has determined the puzzling questions of nomenclature.

In justification of the use of Myxomycetes as a general title it may be said that in this case prevalent usage is not inconsistent with a rational application of the rules of priority. The Friesian designation Myxogastres was applied by its author in 1829 to the endosporous slime-moulds as a section of gasteromycetous fungi. Four years later Link, perceiving more clearly the absolute distinctness of the group, substituted the name Myxomycetes. In the same year Wallroth adopted the same designation, but strangely confused the limitations of the group he named. Wallroth seems to have thought Myxomycetes a synonym for Gasteromycetes Fries. In 1858 DeBary applied the title Mycetozoa to a group which included the then lately discovered Acrasieae with the true slime-moulds, both endosporous and exosporous. For all except the Acrasieae DeBary retained the old appellation, Myxomycetes. Rostafinski adopted DeBary's general name, but changed its application. As it has been shown, since DeBary's time, that the Acrasieae[3] have no true plasmodium, and are therefore not properly, or at least not necessarily, associated with the slime-moulds, there appears no necessity for the term Mycetozoa, and the question lies between Myxogastres and Myxomycetes. Of these two names the former, as we have seen, has[Pg xiii] undoubted priority, but only as applied to the endosporous species. The same thing was true of Link's designation until DeBary redefined it, but having been taken up by DeBary, redefined and correctly applied, Myxomycetes (Link) DeBary must remain the undisputed title for all true slime-moulds, endosporous and exosporous alike.

In arranging the larger divisions of the group the scheme of Rostafinski has been somewhat modified in order to give expression to what the present author deems a more natural sequence of species. The highest expression of myxomycetan fructification is doubtless the isolated sporangium with its capillitium. This is reached by successive differentiations from the simple plasmodium. The æthalium may be esteemed in some instances a case of degeneration, in others of arrested development. In any event in the present arrangement, æthalioid forms are first disposed of, leaving the sporangiate species to follow from plasmodiocarpous as directly as may be.

The artificial keys herewith presented proceed on the same plan and are to be taken, as such keys always are, not as definitive in any case, but simply as an aid to help the student more speedily to reach a probably satisfactory description.

PREFACE TO THE SECOND EDITION

The first edition of this little book having been exhausted long ago, the writer in this second issue takes opportunity to correct sundry errata, typographical and other, and at the same time to incorporate such new information in reference to individual species and to the subject entire as the researches of more recent years may afford.

To Miss Gulielma Lister, of London, the writer expresses his sense of deep obligation for much assistance in settling difficult matters of nomenclature and identification; it will be found as a result that in most instances the same thing in the two volumes, English and American, appears under the same name. There are still differences;[Pg xiv] these result in most cases from different points of view, different estimates or emphasis of characteristics in these ever elusive objects.

To Professor Torrend, formerly of Lisbon, the writer is indebted for a set of European types, and to Professor Bethel, pathologist of Denver, for rich material from the fertile mountains of Colorado and California. To Professor Morton Peck, of Oregon, we are indebted for many notes of the color of plasmodia and for collections of Pacific coast forms. Mr. Bilgram, of Philadelphia, read the manuscript of the genus Physarum and has contributed many rare species. To Dr. Sturgis, of Massachusetts, we are indebted for material from both east and west.

The present volume is intended especially for American readers and is accordingly particularly devoted to a discussion of species so far reported on the western continent; nevertheless it has seemed wise to include a brief description of some other forms as well, and reference to many extra-limital species now generally recognized will be found here and there in connection with the more extended treatment of related American forms.

February twenty-eight, 1921.

[Pg xv]

BIBLIOGRAPHY

The following are the principal works consulted in the prosecution of the investigations here recorded:—

To these may be added the many contributions on the general subject, as these are found in all sorts of current botanical literature; cited everywhere in this volume as occasion offered.[Pg xviii]

[Pg 1]

INTRODUCTORY

The Myxomycetes, or slime-moulds, include certain very delicate and extremely beautiful fungus-like organisms common in all the moist and wooded regions of the earth. Deriving sustenance, as they for the most part do, in connection with the decomposition of organic matter, they are usually to be found upon or near decaying logs, sticks, leaves, and other masses of vegetable detritus, wherever the quantity of such material is sufficient to insure continuous moisture. In fruit, however, as will appear hereafter, slime-moulds may occur on objects of any and every sort. Their minuteness retires them from ordinary ken; but such is the extreme beauty of their microscopic structure, such the exceeding interest of their life-history, that for many years enthusiastic students have found the group one of peculiar fascination, in some respects, at least, the most interesting and remarkable that falls beneath our lens.

The slime-mould presents in the course of its life-history two very distinct phases: the vegetative, or growing, assimilating phase, and the reproductive. The former is in many cases inconspicuous and therefore unobserved; the latter generally receives more or less attention at the hands of the collector of fungi. The vegetative phase differs from the corresponding phase of all other plants in that it exhibits extreme simplicity of structure, if structure that may be called which consists of a simple mass of protoplasm destitute of cell-walls, protean in form and amœboid in its movements. This phase of the slime-mould is described as plasmodial and it is proper to designate the vegetative phase in any species, as the plasmodium of the species. It was formerly taught that the plasmodium is unicellular, but more recent investigation has shown that the plasmodial protoplasm is not only multinuclear but karyokinetic; its cells divide and redivide, as do the reproductive cells of plants and animals generally. Nevertheless, in its plasmodial phase, the slime-mould is hardly to be distinguished from any other protoplasmic mass, may be[Pg 2] compared to a giant amœba, and justifies in so far the views of those systematists who would remove the slime-moulds from the domain of the botanist altogether, and call them animals. The plasmodium is often quite large. It may frequently be found covering with manifold ramifications and net-like sheets the surface of some convenient substratum for the space of several square feet.

The substance of the plasmodium has about the consistency of the white of an egg; is slippery to the touch, tasteless, and odorless. Plasmodia vary in color in different species and at different times in the same species. The prevailing color is yellow, but may be brown, orange, red, ruby-red, violet, in fact any tint, even green. Young plasmodia in certain species are colorless (as in Diderma floriforme), while many have a peculiar écru-white or creamy tint difficult to define. Not only does the color change, sometimes more than once in the course of the life history of the same species, but it may be the same for several forms, which in fruit are singularly diverse indeed, so that the mere color of the plasmodium brings small assistance to the systematist. In fact, the color depends no doubt upon the presence in the plasmodium of various matters, more or less foreign, unassimilated, possibly some of them excretory, differing from day to day.

In its plasmodial state, as has been said, the slime-mould affects damp or moist situations, and during warm weather in such places spreads over all moist surfaces, creeps through the interstices of the rotting bark, spreads between the cells, between the growth-layers of the wood, runs in corded vein-like nets between the wood and bark, and finds in all these cases nutrition in the products of organic decomposition. Such a plasmodium may be divided, and so long as suitable surroundings are maintained, each part will manifest all the properties of the whole. Parts of the same plasmodium will even coalesce again. If a piece of plasmodium-bearing wood be brought indoors, be protected from desiccation by aid of a moist dark chamber, not too warm (70° F.), the organism seems to suffer little if any injury, but will continue for days or weeks to manifest all the phenomena of living matter. Thus, under such circumstances, the plasmodium will constantly change shape and position, can be induced[Pg 3] to spread over a plate of moist glass, and so be transferred to the stage of a microscope, there to exhibit in the richest and most interesting and abundant fashion the streaming protoplasmic currents. As just indicated, the plasmodia follow moisture, creep from one moist substance to another, especially follow nutritive substrata. They seem also to secure in some way exclusive possession. I have never seen them interfered with by hyphæ or enemies of any sort, nor do they seem to interfere with one another. Plasmodia of two common species, Hemitrichia clavata and H. vesparium are often side by side on the same substratum, but do not mix, and their perfected fruits presently stand erect side by side, each with its own characteristics, entirely unaffected by the presence of the other. On the other hand, it is probable that some of the forms which, judged by their different fructifications, and by this alone, are to us distinct, may be more closely related than we suspect, and puzzling phases which show the distinctive marks supposed to characterize different species are no doubt sometimes to be explained on the theory of plasmodial crossing; they are hybrids.

Under certain conditions, low temperature, lack of moisture, the plasmodium may pass into a resting phase, when it masses itself in heaps and may become quite dry in lumps of considerable size, and so await the return of favorable conditions when former activity is quickly resumed. Sometimes the larger plasmodia pass into the resting phase by undergoing a very peculiar change of structure. In ordinary circumstances the abundant free nuclei demonstrable in the plasmodium afford the only evidence of cellular organization. In passing now into the condition of rest, the whole protoplasmic mass separates simultaneously into numerous definite polyhedral or parenchymatous cells, each with a well-developed cellulose wall.[4] When the conditions essential to activity are restored, the walls disappear, the cellulose is resorbed, and the plasmodium resumes its usual habit and structure.

The plasmodial phase of the slime-mould, like the hyphal phase of the fungus, may continue a long time; for months, possibly for years. The reason for making the latter statement will presently appear.[Pg 4] But however long or short the plasmodial phase continue, the time of fruit, the reproductive phase, at length arrives. When this time comes, induced partly by a certain maturity in the organism itself, partly no doubt by the trend of external conditions, the plasmodium no longer as before evades the light, but pushes to the surface, and appears usually in some elevated or exposed position, the upper side of the log, the top of the stump, the upper surface of its habitat, whatever that may be; or even leaves its nutrient base entirely and finds lodging on some neighboring object. In such emergency the stems and leaves of flowering plants are often made to serve, and even fruits and flowers afford convenient resting places. The object now to be attained is not the formation of fruit alone, but likewise its speedy desiccation and the prompt dispersal of the perfected spores. Nothing can be more interesting than to watch the slime-mould as its plasmodium accomplishes this its last migration. If hitherto its habitat has been the soft interior of a rotten log, it now begins to ooze out in all directions, to well up through the crevices of the bark as if pushed by some energy acting in the rear, to stream down upon the ground, to flow in a hundred tiny streams over all the region round about, to climb all stems, ascend all branches, to the height of many inches, all to pass suddenly as if by magic charm into one widespread, dusty field of flying spores. Or, to be more exact, whatever the position ultimately assumed, the plasmodium soon becomes quiescent, takes on definite and ultimate shape, which varies greatly, almost for each species. Thus it may simply form a flat, cake-like mass, aethalium, internally divided into an indefinite number of ill-defined spore cases, sporangia; or the plasmodium may take the form of a simple net, plasmodiocarp, whose cords stand out like swollen veins, whose meshes vary both in form and size; or more commonly the whole protoplasmic mass breaks up into little spheroidal heaps which may be sessile directly on the substratum, or may be lifted on tiny stems, stipitate, which may rest in turn upon a common sheet-like film, or more or less continuous net, spreading beneath them all, the hypothallus. In any case, each differentiated portion of the plasmodium, portion poorly or well defined, elongate, net-like, spheroidal, elliptical, or of whatever shape, becomes at length a[Pg 5] sporangium, spore-case, receptacle for the development and temporary preservation of the spores.[5]

The slime-moulds were formerly classed with the gasteromycetous fungi, puff-balls, and in description of their fruiting phase the terms applicable to the description of a puff-ball are still employed, although it will be understood that the structures described are not in the two cases homologous; analogous only. The sporangium of the slime-mould exhibits usually a distinct peridium, or outer limiting wall, which is at first continuous, enclosing the spores and their attendant machinery, but at length ruptures, irregularly as a rule, and so suffers the contents to escape. The peridium may be double, varies in texture, color, persistence, and so forth, as will be more fully set forth in the several specific descriptions. The peridium blends with the hypothallus below when such structure is recognizable, either directly, when the sporangium is sessile, or by the intervention of a stipe. The stipe may be hollow, may contain coloring matter of some sort, or may even contain peculiar spore-like cells or spores; is often furrowed, and in some cases shows a disposition to unite or blend with the stalks of neighboring sporangia. In many cases the stipe is continued upward, more or less definitely into the cavity of the sporangium, and there forms the columella, sometimes simple and rounded, like the analogous structure in the Mucores, sometimes as in Comatricha, branching again and again in wonderful richness and complexity.

Each sporangium is at maturity filled with numerous unicellular spores. These are usually spherical, sometimes flattened at various points by mutual contact; they are of various colors, more commonly yellow or violet brown, are sometimes smooth (?), but generally roughened either by the presence of minute warts, or spines, or by the occurence of more or less strongly elevated bands dividing reticulately the entire surface. The spores are in all cases small 3–20 µ, and reveal their surface characters only under the most excellent lenses.

Associated with the spores in the sporangium occurs the capillitium. This consists of most delicate thread-or hair-like elements, offering[Pg 6] great variety both in form and structure. The threads composing the capillitium are not to be regarded, even when free, as cells, nor even of cellular origin; probably, as would appear from the researches of Strasburger and Harper, all forms of capillitial threads arise in connection with vacuoles in the protoplasmic mass. "Whether the thread is hollow or solid, simple or branched, free or connected with the peridium or a columella,—these are entirely secondary conditions, depending on the extent and form of the vacuoles."[6] They may occur singly or be combined into a net, they may be terete or flat, attached to the peridial wall or free, simple or adorned with bands or spires and knobs in every variety, uniform or profusely knotted and thickened at intervals, and burdened with calcic particles. In many cases, the capillitium contributes materially to the dispersal of the spores; in others, it doubtless contributes mechanically to the support of the peridial wall, and renders so far persistent the delicate sporangium. For more exact description the reader is again referred to the specific delineations which follow.

The transition from phase to phase requires, as intimated, no great length of time. Tilmadoche polycephala completed the transition from vegetative to fruiting phase in less than twelve hours.

The germination of the spores ensues closely upon their dispersal or maturity and is unique in many respects.[7] The wall of the spore[Pg 7] is ruptured and the protoplasmic content escapes as a zoöspore indistinguishable so far from an amœba, or from the zoöspore of our chytridiaceous fungi. This amœboid zoöspore is without cell-wall, changes its outline, and moves slowly by creeping or flowing from point to point. At this stage many of the spores assume each a flagellate cilium, and so acquire power of more rapid locomotion. The zoöspores, whether ciliate or not, thus enjoy independent existence and are capable of continuing such existence for some time, assimilating, growing, and even reproducing themselves by simple fission, over and over again. This takes place, of course, only in the presence of suitable nutrient media.

Nevertheless the spores of many species germinate quickly simply in water, and a drop suspended in the form of the ordinary drop-culture on a cover-glass affords ample opportunity. In the course of time, usually not more than two or three days, the swarm spores cease their activity, lose their cilia, and come to rest, exhibiting at most nothing more than the slow amœboid movement already referred to. In the course of two or three days more, in favorable cases, the little spores begin to assemble and flow together; at first into small aggregations, then larger, until at length all have blended in one creeping protoplasmic mass to form thus once again the plasmodium, or plasmodial phase with which the round began. Small plasmodia may generally be thus obtained artificially from drop-cultures. Such, however, in the experience of the writer, are with difficulty kept alive. Hay infusions, infusions of rotten wood, etc., may sometimes for a time give excellent results.

The spores of Didymium crustaceum were sown upon a heap of leaves in autumn. An abundant display of the same species followed in the next June; but, of course, the intervening phases were not observed. The most satisfactory studies are obtained by plasmodia carefully brought in directly from the field. A plasmodium that appeared[Pg 8] suddenly and passed to fruit on agar in a petri dish offers a valuable suggestion for further research.

With such a life-history as that thus briefly sketched, it is small wonder that the taxonomic place of the slime-moulds is a matter of uncertainty, not to say perplexity. So long as men studied the ripened fruit, the sporangia and the spores, with the marvellous capillitium, there seemed little difficulty; the myxomycetes were fungi, related to the puff-balls, and in fact to be classed in the same natural order. The synonymy of some of the more noticeable species affords a very interesting epitome of the history of scientific thought in this particular field of investigation. Thus the first described slime-mould identifiable by its description is Lycogala epidendrum (Buxbaum) Fries, the most puff-ball looking of the whole series. Ray, in 1690, called this Fungus coccineus. In 1718, Ruppinus described the same thing as Lycoperdon sanguineum; Dillenius at about the same time, as Bovista miniata; and it was not until 1729, that Micheli so far appreciated the structure of the little puff-ball as to give it a definite, independent, generic place and title, Lycogala globosum ..., etc.[8]

But Micheli's light was too strong for his generation. As Fries, one hundred years later quaintly says, ... "immortalis Micheli tam claram lucem accendit ut succesores proximi eam ne ferre quidem potuerint." Notwithstanding Micheli's clear distinctions, he was entirely disregarded, and our little Lycogala was dubbed Lycoperdon and Mucor down to the end of the century; and so it was not till 1790 that Persoon comes around to the standpoint of Micheli and writes Lycogala miniata. Fries himself, reviewing the labors of his predecessors all, grouped the slime-moulds as a sub-order of the gasteromycetes and gave expression to his view of their nature and position when he named the sub-order Myxogastres. In 1833, Link, having more prominently in mind the minuteness of most of the species collocated by Fries, and perceiving perhaps more clearly even than the great mycologist the entire independence of the group, suggested as a substitute for the sub-order Myxogastres, the order Myxomycetes, slime-moulds. Link's decision passed unchallenged for[Pg 9] nearly thirty years. The slime-moulds were set apart by themselves; they were fungi without question and, of course, plants.

If the hypha is the morphological test of a fungus, then it is plain that the slime-moulds are not fungi. No myxomycete has hyphæ, nor indeed anything at all of the kind. Nevertheless, there are certain parasitic fungi, Chytridiaceae for example, whose relationships plainly entitle them to a place among the hyphate forms that have no hyphæ whatever in the entire round of their life-history. These are, however, exceptional cases and really do not bear very closely on the question at issue.

Physiologically, the fungi are incapable of independent existence, being destitute of chlorophyl. In this respect the slime-moulds are like the fungi; they are nearly all saprophytes and absolutely destitute of chlorophyl. Unfortunately this physiological character is identically that one which the fungi share with the whole animal world, so that the startling inquiry instantly rises, are the slime-moulds plants at all? Are they not animals? Do not their amœboid spores and plasmodia ally them at once to the amœba and his congeners, to all the monad, rhizopodal world? This is the position suggested by DeBary in 1858, and adopted since by many distinguished authorities, among whom may be mentioned Saville Kent, of England, and Dr. William Zopf, of Germany, in Die Pilzthiere, 1885. Rostafinski was a pupil of DeBary's. However, his volume on the slime-moulds was written after leaving the laboratory; and no doubt with the suggestion of his master still before his mind, he adopts the title Mycetozoa, as indicating a closer relationship with the animal world, but our leading authority really has little to say in regard to the matter.[9]

Dr. Schroeter, a recent writer on the subject, after showing the probable connection between the phycochromaceous Algae and the simplest colorless forms, namely, the Schizomycetes, goes on to remark: "At the same point where the Schizomycetous series take rise, there begin certain other lines of development among the most diminutive protoplasmic masses.... Through the amoebæ one[Pg 10] of these lines gives rise on the one hand to rhizopods and sponges in the animal kingdom, on the other to the Myxomycetes among the fungi." This ranges the Myxomycetes, in origin at least, near the Schizomycetes.

The brilliant studies of Dr. Thaxter, resulting in the discovery and recognition of a new group, a new order of the schizomycetes, strikingly confirm the judgment of Schroeter.[10] Here we have forms that strangely unite characteristics of both the groups in question. If on the one hand the Myxobacteria are certainly schizomycetes, on the other they just as certainly offer in their developmental history "phenomena closely resembling those presented by plasmodia or pseudo-plasmodia...." Now the schizophytes certainly pass by gradations easy to the filamentous algæ, and so to relationship with the plants, and the discovery of the Myxobacteriacae, brings the myxomycetes very near the vegetable kingdom if not within it.

All authorities agree that the myxomycetes have no connection in the direction of upward development, "keinen Anschluss nach oben," if then their only relationship with other organisms is to be found at the bottom (centre) of the series only, it is purely a matter of indifference whether we say plant or animal, for at the only point where there is connection there is no distinction.

But why call them either animals or plants? Was Nature then so poor that forsooth only two lines of differentiation were at the beginning open for her effort? May we not rather believe that life's tree may have risen at first in hundreds of tentative trunks of which two have become in the progress of the ages so far dominant as to entirely obscure less progressive types? The Myxomycetes are independent; all that we may attempt is to assert their near kinship with one or other of life's great branches.

The cellulose of the slime-mould looks toward the world of plants. The aerial fructification and stipitate habit of the higher forms tends in the same direction. The disposition to attach themselves to some fixed base is a curious characteristic of plants, more pronounced as we ascend the scale; but by no means lacking in many of the simplest, diatoms, filamentous algae, etc., and it is quite as reasonable to call a vorticella, or a stentor, by virtue of his stipitate form and habit, a[Pg 11] plant as to call a slime-mould an animal because in one stage of its history it resembles an amœba. The total life of an organism in any case must be taken into account.[11] At the outset plants and animals are alike; there is no doubt about it; they differ in the course of their life-histories. The plasmodium is the vegetative phase of the slime-mould. It needs no cell-walls of cellulose, no more than do the dividing cells of a lily-endosperm; both are nourished by organic food and resort to walls only as conditions change. The possession of walls is an indication of some maturity. In the slime-mould the assumption of walls is indeed delayed. Walls at length appear and when they do come they are like those of the lily; they are cellulose. The myxomycetes may be regarded as a section of the organic world in which the forces of heredity are at a maximum whatever those forces may be. Slime-moulds have in smallest degree responded to the stimulus of environment. They have, it is true, escaped the sea, the fresh waters in part, and become adapted to habitation on dry land, but nothing more. It is instructive to reflect that even in her most highly differentiated forms the channel which Nature elects for the transmissal of all that heredity may bestow, is naught else than a minute mass of naked protoplasm. Nature reverts, we say, to her most ancient and simple phases, and heredity is still consonant with apparent simplicity; apparent we say, for as becomes increasingly evident, nothing that lives is simple!

The fact is the Myxomycetes constitute an exceedingly well-defined group, and the question of relationship in any direction need not much perplex the student. Least of all is the question to be settled by anybody's dictum, which is apt to be positive inversely in proportion to the speaker's acquaintance with the subject. No one test can be applied as a universal touchstone to separate plants from animals.[Pg 12] Such is simply petitio principii. Nor is there any advantage at present apparent in attempts to associate slime-moulds with other presumably related groups. Saville Kent's effort to join them with the sponges was not happy, and Dr. Zopf's association of the slime-moulds and monads appears forced, at best; for when it comes to the consideration of the former, their systematic and even morphological treatment, he is compelled to deal with them by themselves under headings such as "Eumycetozoen," "Höhere Pilzthiere," etc. One rather commends the discreetness of DeBary, whose painstaking investigations first called attention to the uncertain position of the group. After reviewing the results of all his labors DeBary does not quite relegate the slime-moulds to the zoölogist for further consideration, but simply says:[12] "From naked amœba, with which the Mycetozoa (=Myxomycetes) are connected in ascending line, the zoölogists with reason derive the copiously and highly developed section of the shell-forming Rhizopoda.... And since there are sufficient grounds for placing the rhizopods outside the vegetable and in the animal kingdom, and this is undoubtedly the true position for the amœbæ, which are their earlier and simpler forms, the Mycetozoa, which may be directly derived from the same stem, are at least brought very near to the domain of zoölogy."

Notwithstanding all the controversy in regard to the matter, the study of the slime-moulds still rests chiefly with the botanists. A simple phylogenetic scheme for thallophytes is offered in the Strasburger text as follows:—

THALLOPHYTA

[Pg 13]

About 500 species of slime-moulds have been described. Saccardo enumerates 443, inclusive of those denominated doubtful or less perfectly known. These 443 species are distributed among 47 genera, of which 15 are represented by but a single species each,—monotypic. In the United States there have been recognized about 300 species. Of those here described, some are almost world-wide in their distribution, others are limited to comparatively narrow boundaries. The greater number occur in the temperate regions of the earth, although many are reported from the tropics, and some even from the arctic zone. Schroeter found Physarum cinereum at North Cape. Our Iowa forms are much more numerous in the eastern, that is, the wooded regions of the state. Physarum cinereum has however been taken on the untouched prairie, and on the western deserts, as also Physarum contextum on the decaying stem of Calamagrostis, far from forest.

As to the economic importance of our myxomycetes, there is no long chapter to write. Fries says: "Usu in vita communi parum admodum sese commendant, sed in œconomia naturæ certe non spernendi. Multa insectorum genera ex eorum sporidiis unica capiunt nutrimenta." However this may be, there is one species which has come to light since Fries's day which is the source of no inconsiderable mischief to the agriculturist. Plasmodiophora brassicae occasions the disease known as "club-root" in cabbage, and has been often made the subject of discussion in our agricultural and botanical journals.[13] Aside from the injurious tendencies, possible or real, of the forms mentioned, I know not that all other slime-moulds of all the world, taken all together, affect in any slightest measure the hap or fortune of man or nation. And yet, if in the economic relations of things, man's intellectual life is to be considered, then surely come the uncertain myxos, with their fascinating problems proffered still in forms of unapproachable delicacy and beauty, not without inspiration.

[Pg 14]

Collection and Care of Slime-Mould Material

On this subject a word may here be appropriate. As just now intimated, specimens may be taken at the appropriate season in almost any or every locality. Beginning with the latter part of May or first of June, in the Northern states, plasmodia are to be found everywhere on piles of organic refuse: in the woods, especially about fallen and rotting logs, undisturbed piles of leaves, beds of moss, stumps, by the seeping edge of melting snow on mountain sides, by sedgy drain or swamp, nor less in the open field where piles of straw or herbaceous matter of any sort sinks in undisturbed decay. Within fifty years tree-planting in all the prairie states has greatly extended the range of many more definitely woodland species, so that species of Stemonitis, for instance, are common in the groves on farms far into Nebraska and Dakota. In any locality the plasmodia pass rapidly to fruit, but not infrequently a plasmodium in June will be succeeded in the same place by others of the same species, on and on, until the cold of approaching winter checks all vital phenomena. The process of fruiting should be watched as far as possible, and for herbarium material, allowed to pass to perfection in the field.

Specimens collected should be placed immediately in boxes in such a way as to suffer no injury in transport; beautiful material is often ruined by lack of care on the part of the collector. Once at the herbarium, specimens may be mounted by gluing the supporting material to the bottom of a small box. Boxes of uniform size and depth may be secured for the purpose. Some collectors prefer to fasten the specimen to a piece of stiff paper, of a size to be pressed into the box snugly, but which may be removed at pleasure. Every pains must in any case be taken to exclude insects. Against such depredators occasional baking of the boxes on the steam radiator in winter is found to be an efficient remedy.

For simple microscopic examination it will be found convenient to first wet the material with alcohol on the slide, then with a weak solution of potassic hydrate, to cause the spores and other structures to assume proper plumpness. A little glycerine may be added or run under the cover if it is desired to preserve the material for further or prolonged study. For permanent mounting nothing in most cases is[Pg 15] better than glycerine jelly. As a preparation, the material should lie for some time in Häntsch's fluid,[14] opportunity being given for evaporation of the alcohol and water. When the material shows the proper clearness and fulness, it may be mounted in jelly in the usual way. Kaiser's formula gives beautiful results. After mounting, the preparation should be sealed with some good cement, as Hollis's glue.

[Pg 16]

[Pg 17]

THE NORTH AMERICAN
SLIME-MOULDS

THE MYXOMYCETES (Link) DeBary

Chlorophyl-less organisms whose vegetative phase consists of a naked mass of multinuclear protoplasm, the plasmodium; reproduced by spores which are either free or more commonly enclosed in sporangia, and which on germinating produce ciliated or amœboid zoöspores, whose coalescence gives rise to the plasmodium.

The Myxomycetes are,—

Sub-Class PHYTOMYXINÆ Schroeter

• 1889. Phytomyxinae Schroeter, Engl. u. Prantl., I., i., pp. 1 and 5.

The parasitic Myxomycetes affecting plants include but few (four or five) species, distributed among four genera. All are parasites in the cells of particular hosts; their vegetative phase is plasmodial and their spores are formed by the simultaneous breaking up of the plasmodium into an indefinite number of independent cells. But a single genus need here concern us,—

Plasmodiophora Woronin

• 1879. Plasmodiophora Woronin, Pringsh. Jahrb., XI., p. 548.

Parasitic in the parenchymatous cells of the roots of living plants, causing noticeable enlargement of the affected organ, producing at length galls, knots, and various deformities and distortions. Spores spherical, smooth, colorless, 16 µ.[Pg 18]

I. Plasmodiophora brassicæ Woronin.

• 1879. Plasmodiophora brassicae Woronin, op. cit.

This species, typical of forms so far reported in this country, infests the roots of cabbages,[15] and produces a very serious disease of that vegetable. In England the malady has long been known under the names "clubbing," "fingers and toes," etc. The roots affected swell greatly, and at length resemble sometimes the flexed fingers of the human hand; hence the English name. As the disease progresses, the roots speedily rot away, to the serious injury of the leaf-bearing portion of the plant. In badly affected fields, sometimes one-half of the crop is utterly destroyed. Careful search continued through several years has not availed to bring this species to my personal acquaintance.

For a full account of the parasitism of this species and its distribution in the United States see Jour. Myc., VII., p. 79; also Bull. 66, Agric. Sta. of Vermont.

Sub-Class EXOSPOREÆ Rost.

• 1873. Exosporeae Rostafinski, Versuch, p. 2.

Spores developed, superficially, outside the fructification, which consists of sporophores, membranous, or slender and branching; spores white, stalked. A single genus,—

Ceratiomyxa Schroeter

• 1889. Ceratiomyxa Schroeter, Engl. u. Prantl, I., i., p. 16. For further synonymy, see under first species.

Sporangia none; spores superficial, borne on erect papillæ or pillars, or even on the inside of minute depressions or pits; each spore surmounting a delicate pedicel or stalk. The spores on germinating give rise to amœboid zoöspores, which undergo repeated divisions, later become ciliate, and at length again amœboid to blend into genuine plasmodia. At maturity the plasmodium gives rise to numerous minute divisions, each of which may lengthen in a direction perpendicular to the surface and bear a spore at the tip.

[Pg 19]

The homologies between the structures just described and the fructification of the ordinary slime-mould are somewhat obscure, if indeed any really exist. Are these minute reproductive bodies spores?—their behavior on germination is unique; are they sporangia?—the arrested development they exhibit is none the less puzzling. Perhaps the sporiferous pillars represent incipient stipes, the spores the uncombined fragments of what might otherwise have coalesced at the summit of the pillar to form a true sporangium.[16]

Several species have been recognized, all referable probably to one or two, or at most, four forms. That universally recognized alike in the literature of the past and in recent studies is,—

1. Ceratiomyxa fruticulosa (Muell.) Macbr.

Plate I., Figs. 7 and 7 a.

• 1729. Puccinia ramosa, bifurcata, etc. Micheli, p. 213, Tab. 92, Fig. 2.
• 1775. Byssus fruticulosa Müller, in Fl. Dan., t. 718, Fig. 2.
• 1778. Tremella hydnoidea Jacquin, Misc., Vol. I., t. 16.
• 1783. Clavaria puccinia Batsch, Elench. Fung., p. 139, Fig. 19.
• 1791. Puccinia byssoides Gmelin, Syst. Naturae, p. 1462.
• 1791. Clavaria byssoides Bulliard, Champ. de la France, t. 415, Fig. 2.
• 1794. Isaria mucida Pers., Römer, N. Mag. Bot., I., p. 121.
• 1801. Isaria mucida Pers., Syn. Meth., p. 688.
• 1805. Ceratium hydnoides Alb. & Schw., Consp. Fung., p. 258.
• 1811. Ceratiomyxa porioides (A. & S.) Schroet., Mycet., p. 26, var.
• 1829. Ceratium hydnoides Fries, Syst. Myc., III., p. 294.
• 1872. Ceratium hydnoides Wor. & Fam., Mem. Acad. Imp., Petersburg.
• 1887. Ceratium hydnoides DeBary, Comp. Morph. Fung., p. 432.
• 1889. Ceratiomyxa mucida Schroeter, Engl. u. Prantl Nat. Pflanz., I., i., p. 16.
• 1893. Ceratiomyxa mucida, Pers., Macbr., Bull. Nat. Hist. Iowa, II., p. 114.
• 1894. Ceratiomyxa mucida Schroet., Lister, Mycetozoa, p. 25.

Plasmodium in rotten wood, white or nearly transparent; when fruiting, forming on the substratum mould-like patches composed of the minute sporiferous pillars, generally in clusters of three or more together; spores white, ovoid, or ellipsoidal, smooth, 10–12 × 6 µ.

Very common, occurring in summer on shaded rotten logs, especially[Pg 20] after warm showers and in sultry weather. Easily distinguishable from all similar moulds by the absence of mycelium or of anything like a hypha. In Europe the plant seems to be in autumn exceedingly common. Micheli not only described the form but figured it, nearly two hundred years ago. Micheli's figure is good, as is that of Mueller, Fl. Dan., l. c. Mueller referred the species to a Linnean genus Byssus, which seems to have included Algæ rather than anything else, if one can determine its limits at all. The same thing is true of Tremella; but this name is now otherwise applied, as are all the other generic names down to Ceratium, Alb. & Schw. But this had been by Schrank preoccupied, 1793. See the reference above for 1889. As for specific name, there seems no reason to depart from the rule of priority, since Mueller's work is determinative.

Ceratiomyxa arbuscula, Berk. & Br., apparently a form of this, is cited from Toronto by Miss Currie. Massee gives it recognition; Lister as varietal. The sporophores are inclined to be simple, stipitate and dendroid.

C. filiforme of the English authors latest named is a wonderful thing and deserves a paragraph here, if not recognition as a distinct species. It occurs rarely; but once it appears, attracts attention. As in the historic species, the sporifers are white, stand more or less erect, but are every way finer and larger. Each individual sporifer rises like a stiff stem, as of white thread, 2–3 mm. high; at top a tuft of fruiting branchlets, more or less distinct. All taken together, we have a dense mat completely concealing the substratum and spreading out sometimes over an area of surprising extent, several centimetres square.

Common everywhere in summer on decaying sticks and wood of every description, especially in wet places. Alaska to Nicaragua, and probably around the world.

2. Ceratiomyxa porioides (Alb. & Schw.) Schroeter.

• 1805. Ceratium porioides Alb. & Schw., Consp. Fung., p. 359.
• 1829. Ceratium porioides Fries, Syst. Myc., III., p. 295.
• 1873. Ceratium porioides Fam. & Wor. Acad. Imp., XX., 3, p. 5.
• 1889. Ceratiomyxa porioides Schroet., Engl. u. Prantl, I., i., p. 16.[Pg 21]
• 1894. Ceratiomyxa mucida Schrœt. var. porioides Lister, Mycetozoa, p. 26.
• 1899. Ceratiomyxa porioides Alb. & Schw. (Schroet.), Macbr., N. A. S., p. 19.
• 1911. Ceratiomyxa porioides Alb. & Schw., Schroet., List. Mycet., p. 26, var.

Entire fructification confluent forming a mucilaginous mass, porose. Pores ample, angulate, at length radiate-dentate. Spores as in the preceding. Plasmodium yellow.

Of these two species Fries remarks: "... Duæ sunt distinctissimæ, inter has vero longa formarum intermediarum series." Famintzin and Woronin not only concur, but consider it were more fitting to place the present species in a distinct genus, as Polyporus is set off from Hydnum. A species based upon the color of the vegetative phase only, unconfirmed by any subsequent differential character in the fruit would seem somewhat hazardous. The color of the plasmodium is incident probably to varied nutrient environment. Pores, however, are usually in evidence.

Iowa, Tennessee, Missouri, etc.; probably common everywhere.

Sub-Class MYXOGASTRES (Fries) Macbr.

• 1829. Sub-order Myxogastres Fries, Syst. Myc., III., p. 67.
• 1833. Sub-order Myxomycetes Link, Handb. der Gew., 3, p. 405.
• 1833. Sub-order Myxomycetes Wallroth, Fl. Crypt., II., p. 333, in part.
• 1858. Class Mycetozoa DeBary, Bot. Zeitung, 1858, pp. 357–365, in part.
• 1889. Class Myxogastres Schroeter, Engl. u. Prantl, Nat. Pflanz., I., i., p. 16.
• 1892. Class Myxogastres (Fries) Massee, Monograph, p. 28.
• 1894. Class Mycetozoa Lister, Mycetozoa, p. 21, in part.

Except as just described, the slime-moulds present abundant, minute, unicellular spores, enclosed in sporangia more or less perfectly defined, and attended by peculiar thread-like structures, free or variously attached and conjoined, the so-called capillitium.

So far as known, the spores on germination give rise to zoöspores, at first amœboid, later ciliate, again amœboid, conjugating in pairs, then, in some cases, at least, coalescing and dividing indefinitely to form the plasmodial or vegetative phase.[17]

[Pg 22]

Key to the Orders of the Myxogastres

Series A

Series B

This sequence is meant to convey the idea that the presence of lime is indicative of differentiation less complete. That the plasmodium should at the outset eliminate, by refusing the unnecessary lime, is indicative of higher rank than that the lime should be carried until the last and then be crystallized out, or excreted by simple desiccation. The circumstance that the excreted lime may sometimes serve a protective purpose in the fruit, does not vitiate the general principle. In Series B the differentiation reaches a climax in the sculptured capillitium of the trichias.

ORDER I

PHYSARALES

Spores violaceous-black. The capillitium usually delicate and thread-like; peridium and capillitium, one or other or both, more or less extensively surcharged with lime. Peridium simple or double. Fructification various.[Pg 23]

This order is recognizable by several characteristics, but is especially marked by the peculiar calcareous deposits which affect the capillitium or peridium, now one, now the other, more often both.

As here defined, the order Physarales includes two distinct families; of the one Physarum, of the other Didymium, is type.

Key to the Families of the Order Physarales

A. PHYSARACEÆ

Key to the Genera of the Physaraceæ

1. Fuligo (Haller) Pers.

• 1753. Mucor Linn., Sp. Pl. II., No. 1656 (?).
• 1768. Fuligo Haller, Hist. Helv., Nos. 1233–1235, in part.
• 1801. Fuligo Haller, Pers. Syn., p. 159.
• 1809. Æthalium Link, Diss., I, p. 42.
• 1829. Æthalium Fries, Sym. Myc., III., p. 92.

[Pg 24]

Sporangia undefined, obscurely woven in and out among each other forming usually a cushion-shaped æthalioid mass. The outer layer sterile, often calcareous, forming a fragile crust, more or less defined. The middle layer sporiferous with calcigerous capillitium. The lowest layer a membranous hypothallus.

The identity of this genus seems to have been recognized first by Haller, op. cit., but by Persoon more closely defined and illustrated. Link simply translated the name into Greek, for reasons less evident now, and in this was followed by Fries. Haller's designation is now probably securely fixed.

The sporigerous median structure of the fructifications, under whatever specific name or names, is entirely confused. Sporangial walls, if ever such there were, are hardly as such recoverable, seemingly indicated only, in the changes to which the æthalium submits as in the ripening the sporogenic plasm passes on to spores.

In the present state of our knowledge the forms of this genus present withal a most perplexing problem. Are they simply phases of a single species, or are they in style and in structure sufficiently constant in their admitted variety, to claim specific rank and separate description?

To follow the example of Greville and recognize in all the literature of two hundred years varied descriptions of a single type,—this were perhaps the easier and speedier disposal of the case. Fries thought so to treat the problem but was unable to keep faith with his own decision; for no sooner he states the genus monotypic than he proceeds forthwith to offer four varieties, a. b. c. d., viz. those by Persoon and others duly recognized as species.

Recent students all, however, seem to find convenience in specific division. All seem disposed to honor Dr. Peck's Fuligo ochracea whether or not by the name he gave; and of other varieties some seem impressed by the constancy of one, some of another characteristic, thus indicating that to careful observers all over the world there are differences that may be recognized, that have been recognized again and again. If there are two species there are certainly more. Out of the gatherings of many years one may set in order not less than five variations in the fruiting of Fuligo, five distinct types[Pg 25] of fructification, to all appearing sufficiently constant for specific recognition.

It will be said, has been said, was said by Fries, that these variations are insignificant, "pendent ex æris constitutione"; but as a matter of fact the several types now in question may be found on the same day, so that evidently something other than the atmospheric environment must determine.

Again it is said that the differences are in external form or color only, the spores in all cases almost if not quite the same. This is true; but specific characters are surface characters in fact: a species morphologically is merely the form in which a kind or genus presents itself. If the presentation be constant, for our convenience we say so, in bestowing a name. Whether in our present treatment the convenience is purely personal, students may decide.

However it all may be, there are in this part of the world many varying presentations of Fuligo capable of illustration and description; the same forms, perhaps, which have attracted the notice of the more acute mycologists in the older history of the subject. Some of these forms we here venture to describe, with such annotation as may show something of present knowledge.

Key to the Species of Fuligo

1. Fuligo muscorum Alb. & Schw.

• 1894. Fuligo muscorum, Alb. & Schw. Lister, Mycetozoa, p. 67.
• 1875. Licea ochracea Peck, N. Y. Rep., XVIII., p. 55.
• 1879. Fuligo ochracea Peck, N. Y. Rep., XXXI., p. 56.
• 1894. Fuligo muscorum, Alb. & Schw., Lister, Mycetozoa, p. 67.
• 1911. Fuligo muscorum Alb. & Schw., Lister, Mycetozoa, 2nd ed., p. 87.

[Pg 26]

Plasmodium orange-yellow. Æthalium globoid, very small, 1 cm. or less, the cortex very thin, greenish yellow; sporangial walls not evident; capillitium well-developed, the numerous calcareous nodes fusiform or often branching, and connected by rather short, transparent internodes; spores coarsely warted, 10–11 µ.

This form seems to differ from F. septica chiefly in its constant diminutive habit of fruiting, in its delicate cortex, and in its spores, brighter, larger, and more coarsely warted. The descriptions and figure by Schweinitz seem referable to nothing else. First reported by Albertini and Schweinitz from Germany; by Schweinitz from the Carolinas; then by Dr. Peck described as a Licea from New York. It seems less commonly collected in the United States.

2. Fuligo cinerea (Schw.) Morg.

Plate X., Figs. 3, 3 a, and 3 b, and Plate XXIII.

• 1831. Enteridium cinereum Schw., N. A. F., No. 2365.
• 1875. Physarum ellipsosporum Rost., Mon. App., p. 10.
• 1884. Æthaliopsis stercoriformis Zopf., Pilzthiere, p. 150.
• 1894. Fuligo ellipsospora Lister, Mycetozoa, p. 67.
• 1896. Fuligo cinerea (Schw.) Morg., Cin. Soc. Nat. Hist., p. 105.
• 1899. Physarum ellipsosporum Rost., Macbr. N. A. S., p. 27.
• 1911. Fuligo cinerea Morg., List., Mycetozoa, 2nd ed., p. 88.

Plasmodium milk-white, watery. Plasmodiocarp long and widely effused, anon winding, here and there reticulate, always applanate; sometimes in form an æthalium, the peridial cortex membranous, firm, thick, and white. Capillitium well-developed, furnished with lime. Spores thin-walled, ellipsoidal, violaceous, plicate-rugose, 14–16 x 11–12 µ.

Not common. Found occasionally in shaded situations on piles of rotting straw or in the woods, especially on detritus of the bracken. The spores are many of them ellipsoidal; some are spherical; all are decidedly spinulose, perhaps might appear plicate-rugulose when dry or shrunken. Calcareous nodules very large and irregular, white.

Schweinitz, loc. cit., described this form as Enteridium cinereum. Rostafinski referred it to the genus Physarum, but was obliged to adopt also a new specific name, as that suggested by Schweinitz was[Pg 27] already in use in the genus Physarum. Zopf, Die Pilzthiere, p. 149, founds a new genus on what seems to be the same form as here considered. This he publishes as Æthaliopsis stercoriformis Z. Massee regards the specimens discovered by Zopf as belonging to the genus Fuligo, and Lister regards Rostafinski's type as Fuligo, and includes Zopf's material under the Rostafinskian species.

This has been described as properly an American form; Lister cites other far localities.

3. Fuligo septica (Linn.) Gmel.

• 1753. Mucor septicus Linn., Sp. Pl. II., No. 1656 (?).
• 1763. Mucor ovatus Schaeff., Fung. Bav., p. 132, Fig. 192.
• 1791. Fuligo septica (Linn.) Gmel., Syst. Nat., p. 1466.
• 1826. Fuligo varians Sommf., Fl. Lapl. Sup., p. 231.
• 1809. Æthalium flavum Link, Diss., I., p. 42.
• 1829. Æthalium septicum Fr., Syst. Myc., III., p. 93.
• 1875. Fuligo varians Sommf., Rost., Mon., p. 134.
• 1892. Fuligo varians Sommf., Macbr., Bull. Lab. Nat. Hist. Ia. II., p. 160.
• 1894. Fuligo septica (Linn.) Lister, Mycetozoa, p. 66.
• 1899. Fuligo ovata (Schaeff.) Macbr., N. A. S., p. 23.
• 1911. Fuligo septica Gmel., Lister, Mycetozoa, 2nd ed., p. 86.

This remarkable and universal species presents as stated many forms and phases. Of these five have been selected as representative.

1. Form a. Fuligo ovata (Schaeff.) Pers.

Plasmodium bright yellow; æthalium pale brown, or yellowish-ochraceous, of variable size and shape, one to many cm. in diameter, and one to two cm. thick, enclosed by a distinct calcareous crust,[Pg 28] which varies in texture, thickness, and color; capillitium well developed but variable in color, form, and extent; spore-mass dull black, sooty; spores spherical, purplish brown, nearly smooth, 7–9 µ.

Under this name may be placed our most common form. Rising with an abundant yellowish creamy plasmodium from masses of decaying vegetation, lumber, sawdust, half buried logs, it creeps about with energy unsurpassed, coming to rest only in some position specially exposed, as the top of a log or stump, the face of a stone or post, or even the high clods of a cultivated field! The fructification is large, yellow, or at most pale ochraceous, the surface when mature extremely friable like dry foam. Bulliard figures this phase well on Plate 424, Fig. 2, and calls it Reticularia (Fuligo) hortensis, from its affecting the soils of gardens. More than thirty fructifications have appeared at one time, varying in size from one to twenty cm. in a field of potatoes, well tilled, and less than an acre in extent! Such is life's perennial exuberance on this time-worn old world of ours!

Schæffer's plate CXII represents probably the same thing. So also Bolton's plate, CXXXIV. Sowerby's Fig. 2 on plate 199, and figures 1 and 2 on Greville's plate 272 possibly also depict this form. Persoon calls this F. vaporaria because it frequents hotbeds and the like, and believes this to represent the "untuosus flavus" of Linnée, although he thinks Schæffer's specimens do not. The calcareous internal structure is white.

2. Form b, F. rufa Pers.

This type of Fuligo is very different from the preceding in form, habit, and color. In form it is much more definite, usually thick, well-rounded and with some solidity. The interior fructification is gray throughout, much less expanded than in a; in fact does not resemble a at all! The cortex is porose but firm, orange at first, but becoming tawny with age, even in the herbarium. Bulliard figures it well, plate 380, Fig. 1, and Sowerby's Fig. 1 on plate 399 is also good, as are also Greville's figure 3 on plate 272 showing the two colors referred to. Not uncommon in the forest from June till September, but far more rare than a: always well-marked, with no other forms associated.[Pg 29]

3. Form c, F. laevis Pers.

Plate X., Fig. 2, 2 a, 2 b.

This is a still more specialized type of the group. The fructification is usually small, smooth, about an inch in diameter and sometimes nearly as thick; the cortex rusty brown, enduring, persisting often when all the sporiferous grayish mass has been distributed through chinks, or from below. The figure 2 on plate X. shows this form. This also is a forest species, is autumnal rather, but may be taken sometimes as early as July. The cortex is not at all porose or spongy, in color reddish or brown, fragile indeed, but not to the touch, in the herbarium enduring for years.

4. Form d, F. flava Pers.

This is hardly F. flava of Persoon; rather of Morgan who uses Persoon's specific designation. Persoon cites Bolton's fig. CXXXIV, which is yellow indeed but is the ordinary presentation of F. septica. The form here considered is remarkable for its delicacy; extremely thin, perhaps one layer only of overlying elongate flexuous sporangia(?), covered by the merest shadow of a cortex in the form of yellow dust, soon lost: the capillitial structure yellow throughout; occurring upon fallen logs in moist dark woods; not common.

5. Form e, F. violacea Pers.

Plasmodium (Morgan teste) dark red, or wine-colored; the æthalium thin, two or three inches wide, covered by a cortex at first dull red and very soft, at length almost wholly vanishing, so that the entire mass takes on a purple-violet tint, upper surface varied with white; capillitium rather open, the more or less inflated, large, irregular nodes joined by long, slender, delicate, transparent filaments; spores dark violet, minutely roughened, spherical, about 7.5 µ.

Ohio, Tennessee. Probably everywhere, but not distinguished from 1.

Professor Morgan, who gave the genus under consideration much attention, regarded F. violacea as a form particularly well-defined. What the value of plasmodic color as a specific character in general, and how far such character is in the present case definitive, because constant, are points yet to be determined.[Pg 30]

4. Fuligo intermedia Macbr. n. s.

Æthalium two to three cm. in greatest diameter, .5–1 cm. thick, covered with a thin, fragile, but not calcareous, greyish or brownish cortex; the spore-mass grey or violaceous-grey, firm, not at all sooty, the sporangia intricate, their walls more or less calcareous; capillitium not conspicuous; spores globose, pale purple, slightly roughened, 10–12 µ.

This form has been repeatedly sent me from Denver, Colorado, by Professor Bethel. I have refrained from publishing it, still anxious to believe that all fuligos on the face of the earth were of one species. In the species next following it must be admitted that the spore-variations are too wide to remain comfortably under shelter of a single specific name. The present species is not F. septica, neither is it F. megaspora; it is F. intermedia.

Colorado; Iowa.

5. Fuligo megaspora Sturg.

• 1913. Fuligo megaspora Sturg., Col. Coll. Pub., p. 443.

Æthalium pulvinate one to three inches in diameter, covered with a thick spongy incrustation of lime, white or yellowish toward the base: sporangia convolute, the walls membranous, brittle, charged throughout with round white granules of lime, 1.5–2 µ in diameter: columella none: capillitium of delicate, colorless, anastomosing tubules, bearing toward the center large, white, branching calcareous nodules; spores spherical, or somewhat oval, dark purple-brown, rough-tuberculate, 15–20 µ.

This species differs as pointed out by Professor Sturgis, chiefly in the character of the spores, their unusual size and roughness.[18]

Colorado; Africa!—Robert Fries.

[Pg 31]

EXTRA-LIMITAL

Erionema Penzig

• 1898. Erionema Penzig, Die Myx. d. Fl. v. Beutenzorg, p. 36.

Sporangia plasmodiocarpous but distinct, cylindrical; capillitium intricate, elastic; nodules few.

1. Erionema aureum Penzig

• 1898. Erionema aureum Penz. l. c.

Sporangia elongate, clustered, pendulous, yellow or grayish yellow, generally stipitate on long flaccid stalks, or sessile and interlacing: stipes yellow, blending with the hypothallus; capillitium intricate, expanding at maturity after the manner of Arcyria to several times the sporangial length, the nodules small, yellow; spores nearly smooth, violaceous-brown, 5–6 µ.

This unique form is near the fuligos which it resembles, especially when sessile, in its intricate sporangia. The spores also are those of the common Fuligo septica. The habit is however entirely different. Mr. Fetch describes clusters in Ceylon, hanging free, four to six cm. in length!

2. Badhamia (Berkeley) Rost.

• 1852. Badhamia Berkeley, Trans. Linn. Soc., XXI., p. 153.
• 1875. Badhamia Rostafinski, Monograph, p. 139.

Sporangia simple; peridial wall simple, thin, breaking irregularly; capillitium formed of abundant, richly anastomosing tubules, filled throughout their entire length with calcareous granules; the nodes often feebly represented; stipe poorly developed or wanting entirely; columella, except in forms sometimes assigned to the sub-genus Scyphium, poorly developed or none; spores frequently adherent in clusters.

This genus is closely related to Physarum, but differs in having the[Pg 32] capillitium calcareous throughout. Forms occur and are included here, in which the capillitium, especially in some parts, is physarum-like, physaroid. Nevertheless, the distinctions hold good as a rule, and are at once diagnostic.

In capillitial differentiation the badhamias are definite and beautiful. The net in a typical species, as B. papaveracea, is throughout uniformly evenly tubular, the calcareous deposits delicate in the extreme, presenting, as the spores disappear, an elegant trabecular structure as if to support the persisting peridium if not the original content. In other forms the capillitium is physaroid, with swollen nodes, but heavily calcareous but not quite throughout. Badhamia, Physarum, Tilmadoche, Craterium present a consistent group, of which Physarum is the generalized expression.

Berkeley's idea of the genus was expressed as follows: "Peridium naked or furfuraceous. Spores in groups, enclosed, at first, in a hyaline sack." Rostafinski, while accepting Berkeley's generic name, redefined it, emphasized the calcareous capillitium, and made reference to the spore-adherence only to assert that Berkeley's description was, in this particular, based on mistaken observation. In some species, the spores do, in fact, show a tendency to cling together, a characteristic which Badham was perhaps first to notice; but that this is occasioned by their being surrounded by a sac or common pellicle has not been proved nor even suggested, by any subsequent investigator. Berkeley's genus was therefore founded upon a slight mistake; but we may conserve his rights in the premises if we write Badhamia (Berk.) Rost., and so keep history straight.

Key to the Species of Badhamia

1. Badhamia ovispora Racib.

• 1884. Badhamia ovispora Racib., Myx. Ag. Cracov., XII., p. 72.

Sporangia sessile depressed-globose or plasmodiocarpous, white or ochraceous, covered by dense calcareous scales; capillitium white, the lime-granules sometimes aggregate at the center to form a pseudo-columella; spores not adhering, brownish-purple ellipsoidal, 8 × 10–10 x 15 µ.

Reported from Bohemia, England, Pennsylvania.

2. Badhamia versicolor Lister.

• 1901. Badhamia versicolor List., Jour. Bot., XXXIX., p. 81.
• 1911. Badhamia versicolor List., Mycetozoa 2nd ed., p. 35.

Sporangia scattered or clustered, minute, .3–.5 mm., grey or flesh-colored, sessile, the calcareous deposits slight; capillitium white or apricot-colored; spores ovoid, 8 × 10–9 × 12 µ, clustered, purplish, and warted at the broader end, elsewhere colorless and smooth.

This little species, as it comes to us, is grey, very uneven in size, .2–.5 mm. and generally irregular in form and habit, perhaps scarce[Pg 34] mature. The capillitium is white, physaroid. The spores furnish the distinguishing character. Sometimes globose, about 9–10. They are most of them definitely and permanently affected in shape by the fact of cluster-association, narrower in the direction of the cluster center. The indications are that these may become globose with maturity.

Colorado,—Bethel; Scotland.

3. Badhamia decipiens (Curtis) Berk.

• 1848. Physarum decipiens Curtis, Am. Jour. Sci., VI., p. 352.
• 1873. Badhamia decipiens Berk., Grev., II., p. 66.
• 1873. Physarum chrysotrichum Berk. & C., Grev. II., p. 66.
• 1876. Badhamia chrysotricha (Berk. & C.) Rost., App., p. 4.

Sporangia gregarious, depressed-spherical or ovate, sessile, occasionally plasmodiocarpous, dull yellow, roughened by the rather large numerous calcareous scales; columella none; capillitium dull orange, strongly calcareous, only slightly widened at the nodes; spore-mass black; spores pale violet, minutely spinulose, free, 10–12 µ.

Among badhamias this and the next species are at once distinguished by the color. If the brief description (Grev., II., p. 66) can be regarded as defining anything, this is the same as P. chrysotrichum Berk. & C. It resembles somewhat P. serpula Morg., but differs externally in color and in the surface scales, which are not perceptible in the Physarum. The present species also resembles Cienkowskia reticulata (Schw.) Rost., but has a different capillitium. See under that species.

Chiefly eastern and American. New England, Pennsylvania, Ohio, South Carolina; reported recently also from Sweden and Germany.

4. Badhamia nitens Berk.

• 1852. Badhamia nitens Berk., Trans. Linn. Soc., XXI., p. 153.
• 1863. Badhamia inaurata Currey, Trans. Linn. Soc., XXIV., p. 156.
• 1873. Badhamia nitens Berk., Rost., Mon. App., p. 3.

Sporangia gregarious or closely crowded, globose or depressed-globose,[Pg 35] .5–1 mm. in diameter, yellow or greenish yellow, rugulose, sessile; capillitium yellow, forming an open net with occasional thickenings at the nodes; spores clustered, delicately roughened, violaceous-brown, 10–12 µ.

This much resembles the preceding species except in the clustered spores, and more commonly aggregate habit. The spores, as usual when clustered, are conspicuously echinulate on the outer side. This did not escape the notice of the author of the species, op. cit.

Colorado, Oregon. Reported from West Indies, Ceylon, various parts of Europe.

5. Badhamia panicea (Fries) Rost.

• 1829. Physarum paniceum Fries, Syst. Myc., III., p. 141.
• 1873. Badhamia panicea (Fr.) Rost., Fuckel, Sym. Myc. Nachtr., 2, p. 71.

Sporangia gregarious or aggregated in closely compacted clusters, globose or hemispherical, sessile, the peridium thin, transparent, thickly dotted with white calcareous scales; stipe none; columella none, although a pseudo-columella sometimes appears, formed by a more dense development of the capillitium near the centre of the sporangium below; capillitium abundantly developed, quite uniformly thickened, but showing an occasional delicate connecting thread, the nodes also somewhat flattened and enlarged; spore-mass black; spores by transmitted light, bright violaceous-brown, minutely roughened, 10–13 µ. Plasmodium is said to be white.

In America this seems to be a purely western species. Specimens are before us from western Iowa and from Colorado, South Dakota, Nevada, and Southern California. It is very well marked, though liable perhaps to be mistaken at first sight for sessile phases of P. notabile or P. cinereum. The capillitium is, however, at once determinative. Colorado; Bethel. Europe generally.

6. Badhamia affinis Rost.

• 1875. Badhamia affinis Rost., Mon., p. 143.

Sporangia aggregated, cespitose and sessile, or sometimes stipitate, depressed above, flat or umbilicate below, the wall grayish white,[Pg 36] rugulose, and more or less calcareous-scaly; the stipe when present erect or sometimes nodding, black or brownish black; hypothallus scanty; columella none; capillitium not abundant, white, the nodes somewhat expanded; spores globose, minutely roughened, violet-brown, large, 16–17 µ.

Chiefly on moss, the pale ashen sporangia generally very small, mounted on the tips of the leaves, sometimes sessile, sometimes with a distinct black stipe in which case the peridium is distinctly umbilicate. Specimens from Kansas referred here have the stipe pale, rugose, long, about twice the sporangium; habitat bark.

Rare. New York, Ohio, Kansas; more recently reported from Scotland and Japan.

There is nothing new to be added here; nor appears any other place to which such material as we have may be referred. New collections no doubt will one day appear, when the identity may, let us hope, be made secure.

Meantime we have a form closely related which may be entered as

Badhamia iowensis Macbr. n. s.

Sporangia gregarious or loosely scattered, depressed globose, .4–.6 mm. in diameter, stipitate, grey, flecked by rather prominent but small rounded calcareous scales: the stipe short, half the diameter of the sporangium, black or very dark brown, without hypothallus but widening above into a shallow expanded base for the sporangia; columella none: capillitium dull yellow, sometimes white, strongly calcareous, physaroid, heavy; spores free, dark brown in mass, pale violet by transmitted light, minutely verruculose, the tiny warts in some areas more densely placed, producing evident shadowy spots, 10–11 µ.

This interesting little species occurs on the lower surface of fallen logs, blocks, etc., in colonies of considerable extent, hundreds of sporangia in a place. The capillitium is comparable to that of B. decipiens or B. panicea; it is physaroid to the extent that an occasional filament may be found non-calcic, and not typically badhamioid as in B. papaveracea, B. macrocarpa. The sporangial base persists, dark brown, bearing traces of the clumsy capillitium, but no columella[Pg 37] real or simulated. Blackhawk Co., Iowa; communicavit Dr. Jessie Parish. See Plate XX., 1, 1 a, 1 b.

Reddish or roseate forms sometimes appear in colonies otherwise as described. It differs from B. affinis in the size and character of the spores, in color and character of the capillitium, habit and surface markings.

7. Badhamia macrocarpa (Ces.) Rost.

• 1855. Physarum macrocarpon Cesati, Flora, XXXVIII., p. 271.
• 1875. Badhamia macrocarpa (Ces.) Rost., Mon., p. 143.

Sporangia scattered or closely aggregate, crowded globose or sub-globose, generally sessile, rugulose, white; the peridium membranous, white above, below yellowish or brown; capillitium not abundant, thoroughly calcareous, the nodes broad, conspicuous, the connecting tubules rigid; columella none; hypothallus scant or none; spore-mass black, spores non-adherent, by transmitted light bright clear brown, thickly spinulose all over, large spherical, 12–15 µ.

Closely resembles externally B. panicea, but is easily distinguished by larger and remarkably spinulose spores, in this particular unrivalled in the entire genus. European authors describe both sessile and stipitate forms. American specimens generally are sessile and for the most part closely crowded, almost heaped; but—Prof. Bethel finds this in winter everywhere on fallen rotting stems of Opuntia and on the bases of dead Yucca leaves, still attached. Associated with the typical phase and often occurring alone on the Yucca leaves is a discoidal form which when first sent in (1908) was called var. gracilis. Presented alone to one ignorant of its history and associations, it would surely pass for a distinct species. This stalked phase is very delicate; the stipe pale brown, or yellow. See Plate II., Fig. 9. See also Sturgis Col. Coll. Pub. XII., 408.

8. Badhamia orbiculata Rex.

Plate XIV., Fig. 4.

• 1893. Badhamia orbiculata Rex. Proc. Phil. Acad., p. 372.
• 1894. Badhamia macrocarpa Rost., Lister, Mycetozoa, p. 34 (in part).
• 1911. Badhamia orbiculata Rex., Lister, Mycetozoa, 2nd ed., p. 37

[Pg 38]

Sporangia stipitate or sessile, orbicular discoidal, irregularly elongated or plasmodiocarpous, averaging about 1 mm. in width, generally stipitate, and when stipitate, flattened or depressed above, plane or slightly umbilicate below; the peridium simple, more or less translucent from the varying number of innate granules, sometimes covered with circular flat masses of lime, gray except the point of attachment to the stipe which is brown; stipe short, black, rough, plicate; capillitium dense at the centre, radiant at the periphery where it meets the sporangial wall, white; spores violaceous black, minutely warted, 12–15 µ.

This is a beautiful species, easily known by its discoidal or almost annulate sporangia mounted upon short dark black stipes. The stipe in western collections is sometimes very short, but generally suffices to raise the sporangium, a little at least, above the substratum. Sessile and plasmodiocarpous forms do occur with the typical stipitate phase, but may be regarded here as elsewhere as indicative of incomplete development. Plasmodium cream-colored, or pale yellow.

Pennsylvania, Ohio, Iowa, Nebraska, South Dakota, Colorado.

9. Badhamia magna Peck.

Plate XIV., Fig. 1.

• 1871. Dictydium magnum Peck, Rep. N. Y. State Mus., XXIV., p. 84.
• 1879. Badhamia magna Peck, Rep. N. Y. State Mus., XXXI., p. 56.
• 1894. Badhamia macrocarpa Rost., Lister, Mycetozoa, p. 34, in part.
• 1892. Bahamia varia Mass. Mon. Myxog., p. 319, in part.
• 1894. Badhamia magna Peck, List., Mycetozoa, p. 33.
• 1899. Badhamia capsulifera (Berk.) Macbr., N. A. S., p. 68.
• 1911. Badhamia magna Peck, Lister, Mycetozoa, 2nd ed., p. 34.

Sporangia globose or ellipsoid, .7–1 mm., pale iridescent, stipitate; peridium thin with slight calcareous deposits, rugulose, opening irregularly, white; stipe long flaccid, straw-colored; capillitium an elegant uniform net, its threads stiffened by slight deposits of lime, the nodes little thickened, badhamioid; spores free, dusky with a shade of violet, minutely spinulose, about 10 µ.

This beautiful species closely resembles some forms of B. utricularis from which it differs chiefly in its unclustered smooth spores.[Pg 39] B. foliicola as recognized here is hardly more than a smaller, short-stemmed form of this; see species next following.

Not rare in the eastern United States and Canada; Iowa. Seems to take the place of B. capsulifera of Europe.

10. Badhamia foliicola Lister.

• 1897. Badhamia foliicola List., Jour. Bot., XXXV., p. 209.
• 1911. Badhamia foliicola List., Mycetozoa, 2nd ed., p. 34.

"Plasmodium orange." Sporangia smaller, about .5–.6 mm., globose or ellipsoidal, iridescent-gray, stipitate or sessile, the peridium thin, rugulose, sparingly calcareous, when empty white; the stipe when present short but yellowish, of the flaccid sort; capillitium badhamioid; spores free, delicately spinulescent, dusky-violaceous, about 12–13 µ.

This has been so far collected but once, on the shores of Lake Okoboji. It was developed, no doubt, on the natural débris of a bur-oak prairie border, and went to fruit on the leaves, stems, and fruiting spikes of a species of Setaria. It may prove to be different from the B. foliicola of Europe; future collections and study must reveal that. Meantime it seems wise to refer it here.

The color of the plasmodium is quoted from Miss Lister; a fact of some importance only when constant and confirmed by other criteria.

Iowa; Toronto,—Miss Currie.

11. Badhamia utricularis (Bull.) Berk.

• 1791. Sphaerocarpus utricularis Bull., Champ., p. 128, t. 417, Fig. 1.
• 1826. Physarum utriculare Chev., Fl. Paris, I., p. 337.
• 1829. Physarum utriculare Fries, Syst. Myc., III., p. 139.
• 1852. Badhamia utricularis (Bull.) Berk., Tr. Linn. Soc., XXI., p. 153.

Sporangia clustered, spherical or ovoid, large, sessile or mounted on long, thin, strand-like stalks, blue-gray, violet-iridescent or cinereous, smooth or more often rugulose; the stipes when present poorly differentiated, as if thread-like filaments and strips of the plasmodium, often branched and always reclining or even prostrate; hypothallus none;[Pg 40] capillitium a large-meshed open network of rather slender tubules, the nodes unequally developed, white with the enclosed lime; spores not strictly adherent though not without some tendency to stick together, delicately warted, bright violet-brown, 10–12 µ.

This species resembles B. capsulifera, but is distinguished by a more strongly rugulose less calcareous peridium and a more profuse development of filamentous stipes, but especially by the character of the spores. The spores of the present species while inclined, when mounted in a liquid, to stay together, nevertheless do not coalesce in heaps as in the related species, nor do they show any differentiation in the episporic markings, these being uniform over the entire spore.

This is one of the finest and perhaps the most beautiful species of this fine genus. It is a forest species, generally to be found on trunks of fallen Populus or Tilia where the fine soft gray colonies often spread for several inches along the ridges and in crevices of the bark.

Colorado (Bethel); Mississippi valley and east.

12. Badhamia capsulifera (Bull.) Berkeley.

• 1791. Sphaerocarpus capsulifer Bull., Champ., p. 139, t. 470, Fig. 2.
• 1801. Physarum hyalinum Pers., Syn. Meth. Fung., p. 170.
• 1852. Badhamia capsulifera Berk., Tr. Lin. Soc., XXI., p. 153.
• 1852. Badhamia hyalina Berk., Tr. Lin. Soc., XXI., p. 153.
• 1875. Badhamia hyalina (Pers.) Rost., Mon., p. 139.
• 1875. Badhamia capsulifera (Bull.) Rost., Mon., p. 141.
• 1894. Badhamia hyalina Lister, Mycetozoa, p. 30.
• 1911. Badhamia capsulifera Lister, Mycetozoa, 2nd ed., p. 31.

Sporangia clustered or gregarious, sessile or sometimes stipitate, globose or obovoid, gray or greenish white, snow-white when empty; the peridium thin, translucent; the stipe, when present, as in B. utricularis, although generally shorter and better developed, yellow or straw colored; capillitium a very loose, open network of white, lime-filled tubules, not much expanded at the nodes; columella none; spore-mass purplish-brown; spores adhering in clusters of five or six to twenty or more, globose, but affected somewhat by mutual pressure, rough throughout, the exposed surface in the cluster, more distinctly warted, 10–12 µ.[Pg 41]

This is Badhamia hyalina (Pers.) Berk., Rost., Mon., p. 139; but Rostafinski himself admits that the two species, here united, as he defined them, are very much alike, having "the same spores and capillitium", differing in the form of the sporangium, an inconstant feature. Bulliard's name has precedence; his descriptions of this and the preceding species are remarkable.

The peculiarly adherent spores distinguish the species from B. utricularis; and the sporangia sessile or with short but strand-like stipes, distinguish it from B. papaveracea.

The description above is for the typical European form. Lister expresses doubt whether this occurs in the United States. The form from Iowa which is the basis for the inclusion of the species in N. A. S. is, we believe, nothing else than B. capsulifera (Bull.) Berk. The form approaches B. populina as this is presented in Colorado. The Iowa specimens are white, aggregate, superimposed, etc., but have the capillitium and spores exactly as described for the type. Accordingly B. populina as this occurs in Colorado has been for years referred to the Berkeley species. The thicker more strongly calcareous peridia constitute, as would appear, the principal difference in the forms from Colorado. See next species.

13. Badhamia populina List.

• 1904. Badhamia populina List. Jour. Bot., XLII., p. 129.
• 1911. Badhamia populina List. Mycetozoa, 2nd ed., p. 32.

Plasmodium white; sporangia sessile, crowded, heaped, large, 1.5 mm., rarely stipitate, globose or ovoid, white; stipe when present brown; capillitial strands broad, calcareous; spores clustered, 16–20 in a cluster, purple-brown, roughened and sometimes marked by obscure ridges and bands, 10–12 µ.

Generally distinguishable by its unusually large calcareous, white sporangia. The peridia are strongly calcareous, shell-like in texture. In some cases the color is tinted with rose.

This species is very near B. capsulifera as recognized in the United States. When white the Colorado material corresponds almost exactly with the forms collected in Iowa, and regarded as representing the[Pg 42] species just named. The Colorado gatherings are more strongly calcareous and the spores sometimes present the variations named. "The Colorado phase of the American form."

Colorado,—Bethel. Europe?

14. Badhamia papaveracea Berk. & Rav.

Plate IX., Figs. 6, 6a, and 6b.

• 1873. Badhamia papaveracea Berk. & Rav., Grev., II., p. 66.
• 1894. Badhamia hyalina var. papaveracea Lister, Mycetozoa, p. 30.
• 1899. Badhamia papaveracea Berk. & Rav., Macbr., N. A. S., p. 69.
• 1911. Badhamia papaveracea Berk. & Rav., List., Mycetozoa, 2nd ed., p. 32.

Sporangia gregarious, globose, large, stipitate, iridescent-gray; the peridium thin, translucent, and containing but little calcareous deposits, smooth or slightly rugulose; stipe very short, but generally distinct, black or very dark brown; hypothallus none; capillitium a network of large meshes with expanded nodes, prominent, white, persistent after the spores have been blown away; spore-mass deep brown; spores adherent as in B. capsulifera, marked in much the same way, and about the same size, 10–12.5 µ

Distinguished by its short, dark, stipe and adherent spores.

Not common. New England, Pennsylvania, Ohio, Maryland, South Carolina, Wisconsin, Iowa.

15. Badhamia lilacina (Fries) Rost.

• 1829. Physarum lilacinum Fries, Syst. Myc., III., p. 141.
• 1875. Badhamia lilacina (Fries) Rost., Mon., p. 145.
• 1892. Craterium lilacinum Mass., Mon., p. 271.
• 1894. Badhamia lilacina (Fr.) Rost., Lister, Mycetozoa, p. 34.
• 1911. Badhamia lilacina (Fr.) Rost., List., Mycetozoa, 2nd ed., p. 38.

Sporangia globose, sub-globose, or obconical, sessile, gregarious or more or less clustered, supported by a thin, continuous, transparent hypothallus; the peridium smooth pale, lilac-brown without, white within; stipe none, although some sporangia have a narrowed base; columella none, the pseudo-columella formed by a more densely aggregated capillitium near the base; capillitium dense, white, strongly[Pg 43] nodulose; spore-mass black; spores dark, violaceous-brown by transmitted light, distinctly warted, or reticulate, the reticulations resembling somewhat those of some of the trichias, as T. affinis, 10–15 µ.

Easily recognizable, generally at sight, by its peculiar color. White forms, however, occur; often lilac-tinted and white from the same plasmodium. A perfectly white colony seems to be rare. Both colors are shown in specimens distributed. N. A. F., 2494.

Common eastward, Ontario, New England, Pennsylvania, Ohio, etc. Not reported west of the Mississippi River.

Whatever the color, the spores are in every case positively diagnostic. The episporic markings are unlike those of any other species in the present order. Dr. Rex describes some New York forms as provided with a short but distinct stipe. Such forms resemble externally Scyphium rubiginosum (Chev.) Rost. The hypothallus is also unique. V. next species.

16. Badhamia rubiginosa (Chev.) Rost.

Plate X., Figs. 1, 1a, 1b, 1c.

• 1826. Physarum rubiginosum Chev., Fl. Par., p. 338.
• 1872. Craterium obovatum Peck, Rep. N. Y. Mus., XXVI., p. 75.
• 1875. Scyphium rubiginosum (Chev.) Rost., Mon., p. 148.
• 1876. Badhamia rubiginosa (Chev.) Rost., Mon. App., p. 5.
• 1892. Craterium rubiginosum Massee, Mon., p. 270.

Sporangia gregarious, obovoid, grayish brown, stipitate, the peridium simple, membranous, above thin, pale, more or less calcareous below, more persistent blending with the stipe; stipe erect, reddish brown or purplish, expanded below into a small hypothallus, above, prolonged within the sporangia more than half its height as a definite columella; capillitium very dense, snow white, long persistent with the lower two-thirds of the sporangial wall; spore-mass dark brown; spores by transmitted light, dark violet or purple-brown, minutely roughened or spinulose, not adherent, 12–14 µ.

This is probably the most common badhamia in the country and in the world. It is found every year, in the woods, on masses of decaying leaves, especially those of various species of oak. The plasmodium is yellow. The fructifications are very distinct, not likely[Pg 44] to be mistaken for those of any other species; the stipes constitute a very prominent feature in every gathering I have seen. Sometimes these are more or less coalescent, especially toward the base, where they are apt to be also wrinkled or longitudinally striate; in other specimens the stipes are well differentiated, long, terete, with little or no hypothallus.

Badhamia curtisii (Berk.) Rost. is according to Lister (Mon., p. 35) a sessile phase of this species. The only specimens known are in the herbarium of Berkeley, now at Kew. The species is based upon a gathering from S. Carolina. Berkeley thought it a didymium, called it D. curtisii.

Reported from western Europe; the typical form abundant in the forested regions of eastern N. America, especially in the Mississippi valley.

17. Badhamia subaquila Macbr.

• 1899. Badhamia subaquila Macbr., N. A. S., p. 64.

Sporangia closely gregarious or crowded, globose or sub-globose, sessile, brown, the peridium a thin but persistent brown membrane, rupturing above irregularly and remaining as a cup after spore dispersal; hypothallus none; capillitium strongly developed, thoroughly calcareous, the meshes large, the nodular thickenings broad, white; spores globose, in mass black, by transmitted light brown, very rough-warted, large, 15–18 µ.

The variety is founded on material sent from Maine by the late Mr. F. L. Harvey. Professor Harvey, upon the authority of Mr. Morgan of Ohio, quotes the species, Bull. Tor. Bot. Club, 24, 67, as B. verna (Somm.) Rost. But the specimens certainly do not conform to description of B. verna. Here the wall corresponds with what is seen in B. rubiginosa; but the spores are much larger, and the capillitial structure very different.

Miss Lister regards this a form of No. 16. So far, the original gathering represents the species; but the woods of Maine are certain one day to send added information.

Rare. On mossy logs, Maine.[Pg 45]

3. Physarum (Persoon) Rost.

• 1794.[19] Physarum Pers., Rom. Neu. Mag. f. d. Bot., I., p. 88, in part.
• 1795. Physarum Pers., Ust. Ann. Bot., XV., p. 5, in part.
• 1801. Physarum Pers., Syn. Fung., p. 168, in part.
• 1829. Physarum (Pers.) Fries, Syst. Myc., II., p. 127, in part.
• 1875. Physarum (Pers.) Rost., Mon., p. 93.

Sporangia plasmodiocarpous, æthalioid or distinct; the peridium usually simple, sometimes double, irregularly dehiscent, more or less definitely calcareous; capillitium a uniform irregular net, dilated and calcareous at the nodes, adherent on all sides to the peridial wall.

This large and cosmopolitan genus is readily recognized by the characters quoted. It may be added that the capillitial threads are always exceedingly delicate, probably tubular, but never filled with lime throughout; the peridium may be almost nude or encrusted with lime, which, where present, is always amorphous, never crystalline; the sporangia when distinct may be either sessile or stipitate, and the stipe in the latter case is often hollow and charged with lime. In capillitium intermediate between Leocarpus and Badhamia, since in the first the capillitium is unequally calcareous, diverse, while in Badhamia the capillitium is intricate and calcareous throughout.

As first set up by its founder, the genus included diverse forms, only one or two of which would be included in the genus as now limited.[20] Persoon, however, was left to develop the matter to suit himself, and in successive works gave, under this generic name, more and more prominence to forms now so referred. Fries, Syst. Myc., III., pp. 127 et seq., still better establishes the genus, though still including forms that, judging from the description, seem to belong elsewhere. Twenty years later Fries revising somewhat his earlier work thought to improve the chances of future students by reducing the number of physarums. This he would do by setting out certain evidently inter-related forms to make a new genus, Tilmadoche.

[Pg 46]

He named two or three species only, leaving his sucessors to add others as occasion offered.[21]

Rostafinski approved the good intention of Fries, but in the Monograph, he entirely re-cast the genus as constituted by Fries; actually called the species 'first cited' a typical physarum! Would not have it in the new genus at all, first or last; but instead took the second species of Fries as the type and added several forms, some from the Friesian list, to make up a respectable group.

Until quite recently writers on the subject have generally approved the course adopted by the Polish author. The arrangement showed features of convenience, even if artificial to a degree. Perhaps we gain advantage in all directions if we treat the original genus Physarum as a whole, but in the key take advantage of Fries' suggestion. We may write—

Key to the Species of Physarum

SECTION I. PHYSARUM

SECTION II. TILMADOCHE

1. Physarum serpula Morgan.

Plate IX., Figs. 6, 6a, and 6b.

• 1831. Physarum reticulatum Alb. & Schw., Schweinitz, N. A. F., No. 2295.
• 1885. Physarum gyrosum (Rost.) Wingate, Ellis, N. A. F., No. 1396.
• 1892. Physarum gyrosum Rost., Massee, Mon., p. 307.
• 1892. Cienkowskia reticulata Rost, Macbr., Bull. Nat. Hist. Iowa, II., 2, p. 150.
• 1894. Badhamia decipiens Berk., Lister, Mycetozoa, p. 33, in part.
• 1896. Physarum serpula Morg., Cin. Soc. Nat. Hist., p. 101.
• 1899. Physarum serpula Morg., Macbr., N. A. S., p. 29.
• 1911. Physarum serpula Morg., Lister, Mycetozoa, 2nd ed., p. 81.

Plasmodiocarp repent, reticulate, forming anon lines, circles, dots, etc., venulose pale yellow, ochraceous, at length whitish, the peridium thin, membranaceous, simple, fragile, but withal persistent, below[Pg 50] united with a hypothallus which is more or less widely produced; capillitium rather scant, but abundantly charged with polygonal nodules of lime, yellow; spore-mass black; the spores, by transmitted light, violaceous, warted, globose, 10–13 µ. Plasmodium, at maturity, greenish-yellow.

A very distinct species not likely to be confused with anything else, although in description, so far as concerns external characters, suggesting Cienkowskia reticulata. The two forms are not at all alike when placed side by side. For details as to the difference, see the description of the species last mentioned.

Apparently not rare in eastern United States, Pennsylvania, Virginia, Ohio, Iowa.

In 1805, Albertini and Schweinitz, Conspectus Fungorum, p. 251, t. 7, Fig. 2, described as Physarum reticulatum, a European form which became the basis of Rostafinski's genus Cienkowskia; see under that genus. Later, 1829, Schweinitz discovered in America a physarum-looking specimen which he took to be the same thing, and accordingly placed in his herbarium under this name, and entered N. A. F. 2295. Rostafinski further renamed another Schweinitzian species Fuligo muscorum calling it, Mon., p. 111, Physarum gyrosum. Wingate and Rex apply in Ellis, N. A. F., this latter name to No. 2295 of Schweinitz. Such a reference is a mistake, judging from Rostafinski's descriptions and from the description and figure of Albertini and Schweinitz (Consp. Fung., p. 86, t. 7, I), and by the testimony of Lister. For further concerning Rostafinski's species, see under Physarum gyrosum, p. 111, Mon.

2. Physarum lateritium (Berk. & Rav.) Rost.

• 1873. Didymium lateritium Berk. & Rav., Grev., II., p. 65.
• 1875. Physarum ditmari lateritium Rost., Mon., App., p. 9.
• 1879. Physarum inequale Peck, Rep. N. Y. Mus., XXXI., p. 40.
• 1892. Physarum chrysotrichum Berk. & C., Massee, p. 300.
• 1894. Physarum inequale Peck, Lister, Mycetozoa, p. 60.
• 1896. Physarum lateritium (Berk. & Rav.) Morg., Jour. Cin. Soc., p. 95.
• 1899. Physarum lateritium (Berk. & Rav.) Morg., Macbr., N. A. S., p. 33.
• 1911. Physarum lateritium Morg., List., Mycetozoa, 2nd ed., p. 82.

[Pg 51]

Plasmodium scarlet. Sporangia gregarious, sessile, globose or sub-globose, or sometimes plasmodiocarpous, yellowish or orange, everywhere, when fresh, spotted with minute scarlet granules; the peridium thin, more or less rugulose; columella none; capillitium delicate, generally yellow, with nodules conspicuous, yellow or reddish; spores violet-brown in mass, by transmitted light pale violet, minutely roughened, 7–9 µ.

A well-marked species easily recognized by the characters cited. The extent of lime deposit at the capillitial nodes varies; sometimes very little. This accounts for Berkeley's generic reference. On the other hand, Lister makes the rounded lime knots "each knot with a red centre surrounded by yellow, round, lime-granules" diagnostic. This pied condition does not come out in any of our specimens. The capillitium in broken specimens soon fades, tends to white, etc.

New York, Pennsylvania, Ohio, Colorado, and south. Ceylon, Java, Brazil.

3. Physarum vernum Somm.

• 1829. Physarum vernum Somm., Fries, Syst. Mycol., III., p. 146.
• 1875. Physarum cinereum (Batsch), Rost., Mon., p. 102, in part.
• 1875. Badhamia verna Rost., Mon., p. 145.
• 1894. Badhamia panicea Rost., List., Mycetozoa, p. 34.
• 1899. Physarum cinereum (Batsch) Rost., Macbr., N. A. S., p. 34 (in part).
• 1911. Physarum vernum Somm., Lister, Mycetozoa, 2nd ed., p. 75.

"Plasmodium white." Sporangia sessile, generally plasmodiocarpous white, nearly smooth; peridium more or less testaceous not scaly, but breaking irregularly; capillitium densely calcareous, the nodules angular, branching, sometimes united to form a pseudo-columella; spores dusky violaceous, rough, 10–12 µ.

Sommerfeldt's description quoted by Fries, l. c., evidently concerned a less calcareous phase. Fries by his annotation relieves somewhat the reader's uncertainty.

Rostafinski calls this a badhamia but describes a physarum, and the form has, as is believed, been consistently confused with P. cinereum by every student of the group from the days of DeBary until now. In the second edition of the Mycetozoa, Lister clears the situation[Pg 52] by transferring the species to Physarum, and calling attention to spore-dimensions. The fact is, the species in external appearance so much resembles P. cinereum, that the unaided eye cannot distinguish one from the other. Curiously enough, Rostafinski describes the form he had before him as "one of the rarest." Doubtless had he gone back to his specimens of P. cinereum he had found plenty, for in Europe it seems abundant everywhere. In this country it is P. cinereum as now defined, that is rarer, although not uncommon. From all connection with Badhamia, as representing B. panicea it should, as would appear, be withdrawn once for all.

4. Physarum sinuosum (Bull.) Weinm.

Plate VIII., Figs. 6 and 6a, and Plate XIX, Fig. 15.

• 1791. Reticularia sinuosa Bulliard, Champ., p. 94; t. 446, Fig. 3.
• 1796. Physarum bivalve Persoon, Obs. Myc., I., p. 6; t. III., Fig. 2.
• 1828. Physarum sinuosum Wein., Fries teste, l. c.
• 1828. Angioridium sinuosum Grev., Scot. Crypt. Fl., 310.
• 1829. Physarum sinuosum Fries, Syst. Myc., III., p. 145.
• 1875. Physarum sinuosum (Bull.) Rost., Monograph, p. 112.
• 1892. Physarum sinuosum Rost., Massee, Mon., p. 305.
• 1894. Physarum bivalve Pers., Lister, Mycetozoa, p. 57.
• 1896. Angioridium sinuosum (Grev.), Morg., Cin. Soc. Nat. Hist., p. 75.
• 1899. Physarum sinuosum (Bull.) Wein., Macbr., N. A. S., p. 28.
• 1911. Physarum sinuosum Wein., Lister, Mycetozoa, 2nd ed., p. 76.

Sporangia distinct or plasmodiocarpous, the plasmodiocarp creeping in long vein-like reticulations or curves, laterally compressed; sometimes distinct and crowded, always sessile. Peridium double; the outer thick, calcareous, fragile, snow-white; the inner delicate, the dehiscence by more or less regular longitudinal fissure. Capillitium strongly developed with abundant white, calcareous granules. Spores smooth, dull violet, 8–9 µ. Plasmodium pale gray, or nearly white.

Easily recognized at sight by its peculiar form, bilabiate and sinuous. Apart from microscopic structure, perfectly described by Fries, Syst. Myc., p. 145. Bulliard called it Reticularia sinuosa. Habitat various, but not infrequently the upper surface of the leaves of living plants, a few inches from the ground. The two sorts of fructification often occur side by side, or merge into one another from the[Pg 53] same plasmodium. Where the substratum affords room the plasmodiocarpous style prevails; in narrower limits single sporangia stand. The calcareous deposit on the peridium is usually very rich and under a lens appears made up of countless snowy or creamy flakes. Forms occur, however, in which these outer calcic deposits are almost entirely wanting; the peridium becomes transparent, the capillitium visible from without. Judging from material before us, this appears to be the common presentation in western Europe. See also No. 5 following.

Widely distributed. New England to the Carolinas, and Louisiana west to South Dakota and Nebraska, Iowa and Washington.

5. Physarum bitectum List.

Plate XIX., Fig. 16.

• 1891. Physarum diderma Rost., List., Jour. Bot., XXIX., p. 260.
• 1894. Physarum diderma Rost., List., Mycetozoa, p. 57.
• 1911. Physarum bitectum List., Mycetozoa, 2nd ed., p. 78.

Sporangia gregarious, sub-globose, sessile or plasmodiocarpous, smooth white or pallid, terete or somewhat compressed; peridium double, the outer wall calcareous, free and deciduous above, recurved and persistent below; the inner, smooth, pale purplish, more persistent; dehiscence more or less irregular beginning at the top; capillitium of large white nodules connected by short hyaline threads; spores generally spinulose, violaceous brown, 9–10 µ.

As suggested by the author of this species it is properly a variety of P. sinuosum; certainly is, as it presents itself in this part of the world. Of the species last named we have compressed forms opening by narrow fissure along their knife-edged summit, with scarce place for capillitium at all between the approaching walls; again we have colonies of sporangia quite terete, calcareous without, opening in fragmental fashion at the top, displaying sometimes the thin membranous inner wall but at length fissured and gaping as in the more usual phase figured by authors, where the plasmodiocarp is simply compressed but not extravagantly thin. Both types occur in the western mountains, forms with and without calcium, fissured by wider or narrower cleft, from the same plasmodium; forms bilabiate and[Pg 54] forms opening at first to display an inner peridium; forms globose with narrow base, but apex cleft, and forms ellipsoidal, yet compressed, opening like the gaping of some tiniest bivalve; did not Persoon say P. bivalve! all are bivalvular at the last! Nay; but what are these? Here are some of the shorter forms become suddenly obovate, and are actually mounted on stipes! Surely variation in the same plasmodium can no farther go![22]

Not rare. Colorado to the Pacific Coast. Evidently a western-American variation of Bulliard's European type. The latter occurs abundantly in Iowa on the shores of Lake Okoboji; otherwise not common.

6. Physarum bogoriense Racib.

• 1898. Physarum bogoriense Raciborski, Hedw., XXXVII., p. 52.

Sporangia sessile, elongate, creeping but not reticulate, semicircular in transverse section, sometimes globose or depressed globose; peridium double, the outer thick coriaceous, yellow or brown, dehiscing stellately into persistent more or less triangular reflected lobes, remote from the thin, colorless inner wall; columella none; capillitium feebly developed, the nodes white, large, isodiametric; spores bright violet, smooth, 7–8 µ.

This species is not uncommon in the mountains of Colorado where it has been taken at various stations by Bethel. It is reported from Pennsylvania and South Carolina. Raciborski describes it from Java.

In habit it is very much like some forms of P. sinuosum but differs in the depressed, rather than compressed sporangia, and in the brown color of the outer peridium.

7. Physarum alpinum G. List.

• 1910. Physarum alpinum G. Lister, Jour. Bot., XLVII, p. 73.

Sporangia globose and sessile or plasmodiocarpous, dull yellow, smooth or scaly; peridium double, the outer wall densely calcareous, separating irregularly from the membranous inner wall; capillitium[Pg 55] densely calcareous, the nodes large, more or less branched, yellow; spores purple brown, closely and minutely warted, 9–14 µ.

This species is based by its author upon a gathering made in California by Dr. Harkness and named by Phillips who received it in England, badhamia inaurata. He seems not to have described it. Since its first appearance, the form has been found repeatedly in the Juras. Specimens are before me from Mt. Rainier believed to be the same. The plasmodiocarpous habit and yellow capillitium separate this from related P. contextum and P. mortoni.

Europe, California, Washington.

8. Physarum diderma Rost.

Plate XVIII., Fig. 9.

• 1875. Physarum diderma Rost., Mon., p. 110.
• 1898. Physarum didermoides var. lividum List., Jour. Bot., XXXVI., p. 162.
• 1899. Physarum diderma Rost., Macbr., N. A. S., p. 30.
• 1911. Physarum testaceum Sturgis, List., Mycetozoa, 2nd ed., p. 79.

Sporangia snow-white, clustered, sessile or narrowly adnate, globose or polygonal by mutual compression; peridium double, the outer dense, fragile, thick, calcareous, the inner delicate, remote, translucent, capillitium well developed, the calcareous nodules white, rounded or angular, sometimes uniting to form a pseudo-columella; spore-mass black; spores purplish, distinctly rough, 10–12 µ.

A beautiful and distinct species. As others in the group with which it is here associated, it is a physarum with the outward seeming of a diderma. It occurs in Europe, therefore it is safe to assume that Rostafinski saw it. So well marked it is that any good description will define it, and Rostafinski describes it perfectly, adequately.[23]

Mr. Lister having used for another species the name we here apply—see under P. bitectum—referred this present form to P. didermoides[Pg 56] Rost., l. c. Professor Sturgis, convinced that such reference was at least doubtful, gave to our American gatherings the distinctive name above, citing specimens from Massachusetts, from Colorado, and from California. Curiously enough he also includes specimens of R. didermoides var. lividum List., sent from England!

Rare! Certainly rare in Europe and so far seldom seen in the United States, though widely distributed. Specimens are before us from Ohio, Michigan, Iowa, Oregon. No doubt the mountains of the north Pacific coast, a region to-day almost unsearched, will yet afford the species in abundance.

As stated Mr. Lister first applied the name P. diderma to a plasmodiocarpous form occurring in England and near P. sinuosum. More lately, Mon., 2nd ed., p. 78, he adopts a new specific name, P. bitectum for the English specimens, and enters P. diderma as a probable synonym for P. lividum R. Evidently our present form as described above has not come to Mr. Lister's view. He says the original type is not to be consulted.

There is really no more merit in this later comparison than in that discarded. The species P. diderma is not P. lividum, but stands as originally delimited, and will, doubtless, some day yet again appear in its own behalf upon the witness-stand of time; when, as before, a Frenchman in DeBary's old-time haunts may rise to give it welcome, brought back by some keen-eyed Polish student eager now in the arts of peace, from Warsaw's shady groves.

9. Physarum contextum Persoon.

Plate IX., Figs. 3 and 3a.

• 1796. Diderma contextum Persoon, Obs. Myc., I., p. 89.
• 1801. Physarum contextum Persoon, Syn. Meth., p. 168.[Pg 57]
• 1829. Diderma contextum Persoon, Fries, Syst. Myc., III., p. 111.
• 1873. Diderma ochroleucum Berk. & C., Grev., II., p. 52.
• 1879. Diderma flavidum Pk., N. Y. Rep. State Mus., XXXI., p. 55.

Sporangia distinct, sessile, densely crowded, sub-rotund reniform more often elongate, interwoven; peridium double; the outer rather thick, calcareous, yellow, or yellowish white, the inner thin, yellowish; capillitium white, containing numerous large, irregular calcareous granules; columella none; spores deep violet, 11–13 µ, covered with minute spinules.

This singular species occurs not rarely upon the bark of fallen twigs, upon bits of straw or grass-stems lying undisturbed upon the ground. In such a position the slime-mould covers, as with a sheath, the entire substratum. The outer peridium, especially its upper part, is entirely evanescent, our Fig. 3 shows the sporangia with upper outer peridium wanting. Not rare in summer and autumn.

New England, New York, Pennsylvania, Ohio, Wisconsin, Illinois, Iowa, Colorado, Oregon, Nicaragua.

10. Physarum conglomeratum (Fr.) Rost.

• 1803. Spumaria granulata Schum., Enum. Pl. Saell., II., p. 196, No. 1419.
• 1803. Spumaria minuta Schum., l. c.
• 1829. Diderma granulatum Schum., Fries, S. M., III., p. 110.
• 1829. Diderma minutum Schum., Fries, l. c., p. 111.
• 1829. Diderma conglomeratum Fries, l. c., p. 111.
• 1875. Physarum conglomeratum (Fr.) Rost., Mon., p. 108.
• 1892. Physarum rostafinskii Massee, Mon., p. 301.
• 1894. Physarum conglomeratum Rost., Lister, Mycetozoa, p. 58.
• 1899. Physarum conglomeratum (Fr.) Rost., Macbr., N. A. S., p. 31.
• 1911. Physarum conglomeratum Rost., List., Mycetozoa, 2nd ed., p. 80.

Sporangia depressed, globose, or irregular, sessile, more or less aggregated, ochraceous-yellow, peridium double, the outer, thick, cartilaginous, at length irregularly ruptured, and reflexed, disclosing the more delicate, ashen-gray, inner membrane which encloses capillitium and spores; capillitium abundant, showing large, white irregular calcareous thickenings which are often consolidated in some sporangia tend to aggregate at the centre; spore-mass brown, spores violaceous, slightly roughened, 8–10 µ.

This beautiful species shows a peridium as distinctly double as in[Pg 58] any diderma. The outer peridium is reflexed exactly as in some species of that genus; is yellow without, white within, and withal long persistent. The capillitium of course distinguishes the species instantly as a physarum. By the size of the spores it is distinguished from the species preceding. This being a decisive specific character the synonymy prior to Rostafinski is somewhat uncertain. The specific name adopted by the Polish author is therefore approved, although perhaps not the earliest.

Rare. The only specimens thus far are from Tennessee and Louisiana.

11. Physarum mortoni Macbr. n. s.

Plate XX., Figs. 2, 2 a.

Sporangia gregarious, clustered but distinct, sessile small, about .75 mm., bright yellow, peridium double. The outer rough, breaking up into comparatively few rather large deciduous scales, the inner peridium white, calcareous, both persisting below to form a distinct cup; capillitium lax, the nodes white, large, angular; columella none; hypothallus none; spores distinctly rough, dark brown with the usual purple shadow, 10–12 µ.

A very distinct little species related, no doubt, to P. contextum, but different in habit. It is never crowded, shows no plasmodiocarpous tendencies, while the outer peridium is generally deciduous except at the base and falls in flakes.

Collected several times in the Three Sisters Mountains of Oregon by Professor Morton E. Peck.

12. Physarum brunneolum (Phillips) Mass.

Plate XX., Figs. 7, 7 a.

• 1877. Diderma brunneolum Phillips, Grev., V., p. 114.
• 1888. Diderma brunneolum Phill., Saccardo, Syll. Fung., No. 1292.
• 1892. Physarum brunneolum Phill., Massee, Mon., p. 280, Figs. 221–222.
• 1894. Craterium pedunculatum Lister, Mycetozoa, p. 71.
• 1911. Physarum brunneolum Mass., Lister, Mycetozoa, 2nd ed., p. 63, Pl. 69, Fig. a.

Sporangia scattered or gregarious, but not crowded, sessile, globose[Pg 59] or sub-depressed; peridium double, thick, smooth or polished, yellow brown, stellately dehiscent, the segments reflexed, white within; columella none; capillitium dense, with nodes numerous, large irregular, internodes thin and short; spores globose, lilac, minutely warted, 6–7 µ.

This form was first described in Grevillea, V., p. 114, as Diderma brunneolum Phillips. Later, students of the specimens preserved by Mr. Phillips, concur that we have to do not with a diderma, but with a craterium, Lister, or physarum, Massee. There seems no reason why we should not respect the decision of Massee, whose description is here quoted in form somewhat abridged. The peridium is about as double as in the many physarums, not more so; the inner membrane so delicate as only occasionally to be revealed except to scrutiny most searching. But the appearance as a whole is as of some brown diderma; only the calcareous capillitium abides to prevent mistaken reference.

When opened by irregular dehiscence from above, the persisting cup-like base of the sporangium recalls Leocarpus fragilis; but then again the capillitium is different.

California, Portugal; Colorado,—Sturgis.

13. Physarum cinereum (Batsch) Pers.

Plate IX., Figs. 4, 4 a, 4 b.

• 1786. Lycoperdon cinereum Batsch, Elench. Fung., p. 249, Fig. 169.
• 1801. Physarum griseum Link, Diss., I, p. 27.
• 1805. Physarum cinereum Persoon, Synopsis, p. 170.
• 1829. Didymium cinereum Batsch, Fries, Syst. Myc., III., p. 126.
• 1829. Physarum plumbeum Fries, Syst. Myc., III., p. 142.
• 1875. Physarum cinereum Batsch, Rost., Mon., p. 102, in part.
• 1896. Physarum plumbeum Fr., Morgan, Myx. Mi. Val., p. 98.
• 1899. Physarum plumbeum Fr., Macbr., N. A. S., p. 35.
• 1909. Physarum cinereum (Batsch) Pers., Torrend, Flore des Myx., p. 183.

Plasmodium watery white, or transparent, wide streaming on decaying sod, etc. Sporangia sessile, closely gregarious, or even heaped, sub-globose, elongate or plasmodiocarpous, more or less calcareous, gray; peridium simple, thin, more or less densely coated with lime; capillitium strongly developed, the nodes more or less richly[Pg 60] calcareous, the lime-knots rounded, angular; spore-mass brown, spores clear violaceous-brown, 6–7 µ, distinctly warted.

This delicate, inconspicuous species is well defined by the characters given. It occurs not rarely on richly manured ground, in meadows, lawns, or even on the open prairie. The plasmodium may form rings several inches in diameter, scattered here and there over a surface several square feet in extent, in fruit ascending the blades of grass, completely covering these with the crowded sporangia. The color of the fruit is well described in the specific name; gray or ashen gray. The spores are very distinctly papillate; in some specimens, however, almost smooth; in few instances, rough.

Common. New England west to the Black Hills and Pacific coast. Cosmopolitan.

The present species well illustrates the difficulty confronting the author of to-day who, discussing a group of microscopic organisms, would fain use the nomenclature of his predecessors, honored, but equipped with insufficient lenses. Here is a species reported common in Europe, observed by every mycologist there, from Micheli down, and yet awaiting adequate description until Rostafinski in his great book, gives the results of microscopic analysis. We are now really dealing with P. cinereum Rost; P. cinereum Batsch is a compliment to certain rather clever water-color drawings.

Rostafinski gives a long list of synonyms, none, it is believed, represent American forms; and without taking careful thought, surely no one would rudely disturb such honorable interment; but, in his description the range of spore-measurement, 7–13.3 µ, gives us pause, and raises the suspicion that possibly, in one case or another, the sepulture were perhaps premature. The range is too great! Perhaps, in the series offered in confirmation, small-spored forms represent one species, large-spored, something else?

European students may decide this at their leisure. But Rostafinski having, not without much labor, practically completed his review of the physaroid forms had almost finished the last genus Badhamia, when his mind perhaps returned, no doubt with some lingering misgivings, to the thirteenth species in his physarum list. There were there, he recalled, some large-spored specimens which[Pg 61] had rather badhamioid capillitium. The sessile physarums of Fries were also before him, those especially, "floccis albis." Of these one shall be B. panicea, one B. lilacina and one B. verna, described as having rather delicate colorless capillitial tubes combined in a loose net, the calcareous deposits about the enlarged intersections scanty, the spores 12.5 µ.

The description of the fructification as a whole is a condensed statement of that which describes P. vernum, and all taken together indicates some physarum. See now No. 3 preceding, p. 51.

P. plumbeum Fr. belongs here. It has similar spores, the only difference is a less calcareous peridium and more scattered habit of fructification with more nearly regular, depressed-globose sporangia.

P. cinereum Pers. as cited by Link, op. cit., is apparently a badhamia, may be P. vernum, while P. griseum is probably the present species.

14. Physarum virescens Ditmar.

Plate VIII., Figs. 7, 7 a, 7 b.

• 1817. Physarum virescens Ditmar, Sturm, Deutsch. Fl. Pilze, I., p. 123, Pl. 61.
• 1875. Physarum ditmari Rost., Mon., App., p. 8.
• 1892. Physarum ditmari Rost., Macbr., Bull. Lab. Nat. Hist. 1a., II., p. 155.
• 1894. Physarum virescens Ditmar, Lister, Mycetozoa, p. 65.
• 1909. Physarum virescens Ditmar, Torrend, Flo. d Myx., No. 207.
• 1911. Physarum virescens Ditmar, Lister, Mycetozoa, 2nd ed., p. 83.

Sporangia sessile, crowded or heaped in small bunches, a dozen or more sporangia in one pile, spherical, ovoid or elongate, yellow or greenish yellow; peridium thin, fragile; capillitium delicate, with rather small, irregular, yellowish, calcareous nodes; columella none; spores bright violet, minutely roughened, 7–9 µ.

This species occurs more commonly on moss-tufts, with which it is frequently con-colorless, or escaped on dead leaves, etc. The peridium is flecked with calcareous scales or grains stained yellow or green, and to these the whole fruit owes its peculiar color. The color and aggregate, heaped sporangia are distinctive macroscopic characters.

In the Monograph, p. 113, Rostafinski adopted properly Ditmar's name for this species. Upon later consideration, in the Appendix,[Pg 62] p. 8, he changed the name, writing P. ditmari, on the ground that virescens was descriptive of a character to which the species in question occasionally refuses to conform. Most authors since Rostafinski have simply accepted his suggestion, so that the species is often entered P. ditmari Rost. P. virescens is certainly to be preferred. N. A. F., 2692.

Canada, New England, New York, Pennsylvania, Ohio, Iowa, Black Hills, South Dakota.

15. Physarum rubiginosum Fries.

• 1817. Physarum rubiginosum Fries, Symb. Gast., p. 21.

Plasmodium scarlet. Sporangia globose or cylindric, sessile or sometimes narrowed to a stem-like base as if short-stipitate, olivaceous brown with sometimes a flush of red; the peridium simple, thin rugulose or plain, the calcareous scales few, or apparently included; columella none; capillitium dense, the nodules rather large, angular, rusty brown; spores dull violaceous, gently roughened, about 10 µ.

A beautiful well-marked species, but evidently rare in North America. Our only typical specimens are from the gatherings by Mr. Wingate, part of which is by Lister referred to this species, Mycetozoa, 2nd ed., p. 82.

P. rubiginosum Fr. in the N. A. S., 1899, is based on certain west coast specimens now known as Badhamia decipiens Berk.

In Colorado there occurs a plasmodiocarpous form of the species. It has the characteristic spore and capillitium but in form and habit differs very decidedly. The fructification is a delicate netted plasmodiocarp, the tubule about .5 mm., bright red; the peridium simple, cartilaginous, dehiscent from above, and flecked with just here and there a red calcareous scale.

Collected at Palmer Lake; Professor Bethel.

16. Physarum instratum Macbr. n. s.

• 1899. Physarum thejoteum Macbride, N. A. S., p. 36, not Fries, as cited.
• 1911. Physarum virescens Ditmar, Lister, Mycetozoa, 2nd ed., p. 83.

Sporangia very small, closely crowded on a delicate, more or less[Pg 63] visible hypothallus, often connate, but not superimposed, sub-spherical, dull orange, brownish or tawny; peridium thin, violaceous, covered with very minute yellow calcareous scales; columella none; capillitium lax, sometimes almost wanting; the nodules small, yellowish or brownish, occasionally confluent; spore-mass violaceous, spores by transmitted light, violet-tinted, smooth or nearly so, 6–7 µ.

Not uncommon in the Mississippi valley, where it sometimes is passed by the collector as an immature form of some other species. The appearance is very characteristic, unlike P. virescens in both habit, size, and color. Colonies are quite often three inches in length. The most common habitat seems to be rotten oak, especially fragments of charred logs, etc.

Ohio, Illinois, Missouri, Iowa, Nebraska.

This species presents a decidedly well-marked form, so much so that it may be easily recognized at sight, without a lens. It therefore requires special discussion, and although in the spore-characters and some minor but not determinative details it agrees with P. virescens Ditm. to which it is by European authors sometimes referred, it seems nevertheless deserving of specific recognition, since in its entire habit and expression it is not only completely different but is constant in its specific peculiarities, much more so than is the suggested related form.

In the first edition of this work, the form was referred to Physarum thejoteum of Fries. This was the judgment of our American colleague, Professor A. P. Morgan whose work in this group is widely recognized. Fries admits, Syst. Myc., III., p. 142, that while he deems P. thejoteum very distinct, he yet has not seen P. virescens Ditm.! Since our form apparently does not occur in Europe, specimens which the distinguished author had before him were doubtless representatives of the now commonly recognized species of Ditmar.

For these reasons it seems appropriate to give the American type a suitably descriptive title.

17. Physarum megalosporum MacBr.

Plate XVI., Figs. 7 and 7 a.

• 1917. Physarum melanospermum Sturgis, Mycologia, Vol. IX., p. 323.

[Pg 64]

Sporangia gregarious, sessile, or short stipitate depressed, annulate, or at least umbilicate above, white or anon roseate, about .75 mm; stipe, when present, short, thick, black or dark brown! hypothallus none; columella none; capillitium strongly calcareous, an abundance of irregular white nodules burden the delicate net; spores dark sooty brown with a shade of purple by transmitted light, verruculose, 12–13 µ.

This species is recognizable at once by its regular, uniform, depressed, annulate or pitted sporangia, scattered evenly over the habitat of rotten leaves or wood. It suggests a didymium in its form and habit, but is near a badhamia. Colorado; Bethel, 1908.

18. Physarum confertum Macbr. nom. nov.

Plate XV., Figs. 1, 1 a, 1 b.

• 1899. Physarum atrum Schw., Macbr., N. A. S., p. 36.
• 1911. Physarum atrum Schw., Lister, Mycetozoa, 2nd ed., p. 74.

Sporangia small about .2–.3 mm. in diameter, gregarious, confluent, clustered or heaped, dull violaceous brown; peridium thin, more or less transparent, generally limeless but sometimes lightly sprinkled with minute white flecks: capillitium scanty, the calcareous nodes small, rounded, elongate, white! columella none; spores violet-brown, distinctly warted, 10–12 µ.

Having been assured on information believed trustworthy that the Schweinitzian herbarium confirmed the identity of the species before us, in the first edition of this work the form was listed as P. atrum Schw. Meantime in the herbarium referred to, at Philadelphia the original type of P. atrum still exists. My valued correspondent, Mr. Hugo Bilgram, has recently given it careful study. It is a limeless P. didermoides (Pers.) R.! Small wonder we have had trouble! Exit Physarum atrum Schw.

The species is not uncommon, especially eastward; has been generally ignored for reasons cited.

Distinguished from everything else by the color and small size of the heaped sporangia. It resembles some phase of P. virescens where the sporangia are small and somewhat heaped or rather aggregated,[Pg 65] and scantily supplied with lime; but in such case the lime is yellow and the spores are small.

This species has also been constantly referred to our confused P. cinereum, P. plumbeum, etc., but Schweinitz, who certainly had seen P. cinereum in Europe, since he cites it, under several forms, in the Conspectus, found the species in America and proceeded in Pennsylvania in December to find something else, very different as he thought, and in fact. He called this new discovery P. atrum, "beautifully reticulate", he says "like P. cinereum but larger."

Most American students in an effort to keep faith with their pioneer mycologist, have taken cue from the specific name, looking for something black, heedless that in Pennsylvania almost any delicate thing has 'dark looks' in the middle of the winter! Berlese in Saccardo Syll. VII., p. 350, regarding P. atrum as a synonym, writes for the black American specimens, P. reticulatum, emphasizing another Schweinitzian descriptive adjective. But P. atrum Schw. has had place in literature to this hour.

19. Physarum melleum (Berk. & Br.) Mass.

• 1873. Dydymium melleum Berk. & Br., Jour. Linn. Soc., XIV., p. 83.
• 1873. Didymium chrysopeplum Berk. & C., Grev., II., p. 53.
• 1876. Physarum schumacheri Spr. var. melleum Rost., Mon., App., p. 7.
• 1892. Physarum melleum Massee, Mon., p. 278.
• 1896. Cytidium melleum (Berk. & Br.), Morg., Jour. Cin. Soc., p. 83.
• 1899. Physarum melleum (Berk. & Br.), Mass., Macbr., N. A. S., p. 47.
• 1911. Physarum melleum Mass., Lister, Mycetozoa, 2nd ed., p. 46.

Sporangia scattered, stipitate, globose, flattened below, clear yellow or honey colored; stipe short, about equaling the sporangium, pure white, somewhat wrinkled; columella small but distinct, white; hypothallus none, capillitium abundant, open, snow-white, with rather large angularly stellate nodes; spore-mass brown, almost black; spores by transmitted light, pale violet or lilac-tinted, almost smooth, 7.5–10 µ.

Easily distinguished by its white stipe, columella and capillitium in contrast with yellow peridial walls. N. A. F., 1395. Massee refers this number erroneously to P. schumacheri Rost. The description[Pg 66] and specimen do not correspond. By that name the species has however, been hitherto known in the United States.

Eastern United States, common; rare west of the Mississippi.

Reported from Brazil, Japan and the tropic islands round the world. Portugal.

20. Physarum citrinum Schumacher.

• 1803. Physarum citrinum Schum., Enum. Pl. Saell., II., p. 201.
• 1911. Physarum citrinum Schum., List., Mycetozoa, 2nd ed., p. 51.

Sporangia gregarious, scattered, globose, somewhat flattened below, pale yellow, citrine, stipitate; the peridium thin, covered almost completely with small calcareous scales; stipe stout, erect, fragile, tapering upwards, furrowed, opaque, arising from a small hypothallus which is anon continuous from one sporangium to the next; columella small, conical, yellow; capillitium a rather dense, delicate network, the calcareous nodules yellow, numerous, roundish, and generally small; spore-mass black; spores under the lens violaceous, almost smooth, about 8 µ.

This species seems to be rare in the United States. It resembles somewhat P. melleum, from which it is distinguished by its yellow stipe. P. galbeum is a smaller form, and lacks the columella. Rostafinski strangely confused the synonymy here, including even P. rufipes Alb. & Schw.

New England, Ohio, Colorado.

21. Physarum globuliferum (Bull.) Pers.

• 1791. Sphaerocarpus globuliferus Bull., Champ., Pl. 484, Fig. 3.
• 1801. Physarum globuliferum Pers., Syn., p. 175, T. III., Figs. 10, 11, 12.
• 1829. Diderma globuliferum Fries, Syst. Myc., III., p. 100.
• 1876. Physarum petersii farlowii Rost., Mon., App., p. 6.
• 1879. Physarum albicans Peck, Rep. N. Y. Mus., XXX., p. 50.
• 1893. Physarum columbinum Macbr., Bull. Lab. Nat. Hist. Iowa, II., 384.
• 1899. Physarum globuliferum (Bull.) Pers., Macbr., N. A. S., p. 45.
• 1911. Physarum globuliferum Pers., Lister, Mycetozoa, 2nd ed., p. 48.

Sporangia gregarious, stipitate, globose, or slightly depressed above, pale blue-gray or pure white; stipe sometimes equal to the sporangium, generally longer, slender, slightly wrinkled, white, or yellow, pallid,[Pg 67] when longer tapering upward; columella white, conical, sometimes obsolete; hypothallus none; capillitium dense, but delicate, persistent, a close network of hyaline threads, with white or yellowish nodes sparingly thickened and calcareous, many without lime; spore-mass brown; spores by transmitted light, violet, minutely warted, 7.5–9 µ. Plasmodium greenish-yellow.

This species, very common eastward, rare west of the Mississippi, is at once very beautiful and very variable. Its several phases have been again and again observed and described too often by distinct specific or varietal names. A form from New York, with long, white stems and almost pure white sporangia, is P. albicans Peck. Forms occur like P. albicans, but flushed with rose throughout. From New England, specimens sent Rostafinski were by him deemed a variety of P. petersii Berk. & C., and called P. petersii var. farlowii Rost. By this name the species has been generally distributed in this country. N. A. F., 1120. Most gatherings of this species have small, somewhat ochraceous, sporangia, and pale yellow, or somewhat rusty, stipes. These latter, with somewhat heavier stem, represent Physarum simile Rost. A form collected sparingly in Iowa has short, white stipes and blue gray sporangia one-third larger than observed in the eastern types. This was recorded, l. c., as P. columbinum Macbr.; name already in use. The spores in the Iowa specimens are also a little larger, 8–10 µ. Pale cyanic and roseate forms also sometimes occur in late fruitings; see next species.

In all phases the persistent tenacity of the capillitium is a striking characteristic well noticed by Fries (l. c., p. 101): "Peridia a gleba omnimo libera, dein tota diffracta, evanescentia, ... capillitio compacto forma servata persistente." The peridium, except a small part below, all falls away, leaving the capillitium apparently intact, crowded with spores.

From England to Iowa; Canada, south to Louisiana and Mexico; apparently, in one form or another, cosmopolitan.

22. Physarum lilacinum Sturgis & Bilgram.

• 1917. Physarum lilacinum Sturg. & Bilg., Mycologia, Vol. IX., p. 323.

Sporangia gregarious, stalked, globose, erect, pale-lilac to pale[Pg 68] Indian-red in color, 0.5 mm. in diameter; sporangium-wall membranous, beset with rounded masses of lilac or reddish lime. Stipe erect, broad-based, tapering upwards, calcareous, furrowed, paler than the sporangium or concolorous, 0.7–0.9 mm. long, about 0.1 mm. thick, columella conical or columnar, capillitium delicate, rigid, persistent; lime-knots small, rounded, composed of large, pale lilac, or reddish, spherical granules. Spores pale-brown, almost smooth, 8–9 µ.

Vicinity of Philadelphia,—Bilgram.

23. Physarum murinum Lister.

• 1894. Physarum murinum Lister, Mycetozoa, p. 41.
• 1899. Physarum ravenelii (Berk. & C.) Macbr., N. A. S., p. 48.
• 1911. Physarum murinum Lister, Mycetozoa, 2nd ed., p. 50.

Sporangia scattered, globose or perfectly spherical, ashy-brown, rugulose, stipitate; stipe elongate, pale brown, erect, generally tapering upward, calcareous, brittle; hypothallus none; columella short, hemispherical or bluntly conical; capillitium dense, much as in P. globuliferum, the calcareous nodules, umber, brownish or orange-yellow, small; spore-mass brown; spores by transmitted light, bright lilac, almost smooth, 7–9 µ.

A very distinct species, easily known by its peculiar drab-colored peridium and dull brown stalks. The author of the species allows for the capillitial nodes none other tint but brown. Under direct illumination many gatherings, especially where the sporangia are well blown out, show nodules of a bright orange tint.

Not rare in the eastern United States, to Missouri and Iowa. Reported also from western Europe.

Mr. Lister finds Didymium ravenelii Berk. & C., on which P. ravenelii (Berk. & C.) Macbr. is founded, referable to P. pulcherripes Pk.

24. Physarum pulcherrimum Berk. & Rav.

• 1873. Physarum pulcherrimum Berk. & Rav., Grev., II., p. 65.
• 1875. Physarum pulcherrimum (Berk. & Rav.) Rost., Mon., p. 105.
• 1879. Physarum atrorubrum Peck, Rep. N. Y. Mus., XXXI., p. 40.
• 1899. Physarum pulcherrimum Berk. & Rav., Macbr., N. A. S., p. 49.
• 1911. Physarum pulcherrimum Berk. & Rav., Lister, Mycetozoa, 2nd ed., p. 50.

[Pg 69]

Plasmodium dark red. Sporangia scattered or gregarious, globose, even, or somewhat wrinkled, dark red, stipitate; stipe cylindric, even, sub-concolorous or blackish; columella small or none; capillitium free from spores, whitish, with a slight pinkish tinge; spores dark brown in mass, dark red when separated, globose, smooth, 7.5–8.5 µ.

The capillitium is very delicate, and when cleared of spores the knot-like thickenings are seen to be very small and of a dark red color, to which is probably due the pinkish tinge which marks the whole. A part only of the thickenings are filled with lime granules. The dark red granules of the sporangium walls are abundant and appear to form a continuous crust.

This is P. atrorubrum Peck, and his description, l. c., has been closely followed. The very brief description in Grevillea, however, antedates the New York publication and, all inadequate as it is, no doubt applies to the same thing.

Not rare. New York, Pennsylvania, Ohio, Missouri, Iowa.

25. Physarum pulcherripes Peck.

• 1805. Physarum aurantiacum var. rufipes Alb. & Schw., Consp. Fung., p. 94.
• 1829. Diderma rufipes (Alb. & Schw.) Fries, Syst. Myc., III., p. 101.
• 1873. Physarum pulcherripes Peck., Bull. Buff. Soc. Nat. Hist., I., p. 64.
• 1873. Didymium erythrinum Berk., Grev., II., p. 52.
• 1873. Didymium ravenelii Berk. & C., Grev., II., p. 53.
• 1873. Physarum petersii Berk. & C., Grev., II., p. 66.
• 1875. Physarum schumacheri Spr. var. rufipes Alb. & Schw., Rost., Mon., p. 99.
• 1894. Physarum pulcherripes (Peck), Lister, Mycetozoa, p. 41.
• 1896. Cytidium rufipes (Alb. & Schw.) Morg., Jour. Cin. Soc. Nat. Hist., p. 81.
• 1899. Physarum rufipes (Alb. & Schw.) Morg., Macbr., N. A. S., p. 50.
• 1911. Physarum pulcherripes Peck., List., Mycetozoa, 2nd ed., p. 49.

Sporangia gregarious, dark-colored, sprinkled with orange flakes of lime, globose, the wall thin, deciduous, stipitate; stipe slender, erect, deep red, sometimes black below, pale or orange above, and supported on a well-developed hypothallus; columella scant or none; capillitium dense, the meshes and nodes unusually small and delicate, the latter reddish or yellow; spore-mass black; spores by transmitted light, violet-tinted, 8–10 µ., almost smooth.

The striking contrast of color between sporangia and stipes renders this species at sight, quite distinct from any related form. The[Pg 70] peridia in the specimens before us are black or iridescent-black sprinkled more or less profusely with orange lime granules which sometimes cover all but the base. The stipe, springing from a small hypothallus, is dark red below for about one-fourth its height, then vermillion, above expanding slightly beneath the peridium; the columella scant or none. The capillitium is an elegant delicate net, with numerous small, uniformly regular, calcareous nodes, orange; by transmitted light, yellow. The spores, brown in mass, are, by transmitted light, pale violet, slightly papillose, 8–10, mostly about 8 µ. The plasmodium is probably yellow.

This species is no doubt related to P. psittacinum. It is, however, much smaller, has a calcareous stipe, and a much less variegated peridium, and generally a small columella.

It is also akin to P. globuliferum and to P. murinum, P. petersii Berk. & C. is reported the same thing.

26. Physarum penetrale Rex.

Plate XV., Figs. 6, 6 a.

• 1891. Physarum penetrale Rex., Proc. Phil. Acad., p. 389.
• 1899. Physarum penetrale Rex., Macbr., N. A. S., p. 55.
• 1911. Physarum penetrale Rex., List., Mycetozoa, 2nd ed., p. 36.

Sporangia scattered, erect, stipitate, generally ellipsoidal, pyriform, rarely globose; peridium membranaceous semi-transparent, studded sparsely with rounded, pale yellow or yellow-gray lime-granules, rupturing to the base into two or four segments; stipe variable, slender, subulate, rugulose, flattened laterally toward the base, translucent, dull red or golden red in color; columella four-fifths the height of the sporangium, concolorous with the stipe, acuminate; capillitium dense, persistent, the nodes frequently calcareous, rounded, yellow; spore-mass brown, spores nearly smooth, brownish, 6–7 µ.

Readily recognizable by the elongate sporangia and the lengthened columella unique among physarums. The capillitial nodes are at first pale yellow, but tend to whiten on exposure. The spores when highly magnified show delicate spinulescence.

Maine, New York, Pennsylvania, Ohio, Europe, Java.[Pg 71]

27. Physarum luteo-album Lister

• 1904. Physarum luteo-album List., Jour. Bot., XLII., p. 130.
• 1911. Physarum luteo-album List., Mycetozoa, 2nd ed., p. 48.

Sporangia gregarious, sub-globose, large, about 1 mm. in diameter, yellow shading into white, orange or olivaceous, smooth or rugulose, stipitate; stipe stout, smooth, .5–1 mm. high, yellow or orange above, white below, cylindric, lime-stuffed; columella large, sub-globose or clavate, yellow; capillitium either of very slender pale yellow, threads, branching at acute angles and anastomosing or of broad, yellow simple or forked strands, persistent after spore-dispersal; nodules few, small, linear or fusiform; spores purple-brown, spinulose, 10–12 µ.

This species, originally described from England and northern Europe has more recently been identified in material sent by Professor Sturgis from Colorado. In description the form is well marked; evinces apparently great variation alike in form, color, and structure.

The material we have, however, is poor, badly weathered.

The general plan of structure corresponds very well with Fries' idea of his genus Tilmadoche, although the present species would seem, by very grossness, strangely out of place with the tilmadoches. But the singular, didermoid, evenly branching, threads of the capillitium, bearing their slender spindle-shaped burdens of lime are very suggestive; it is a diderma gone wandering into the camp of the physarums if one may judge from Miss Lister's graphic plate.

The specific name selected for this peculiar form has once before done service, but apparently for something quite dissimilar. Schumacher, Enum. Pl. Saell. II., p. 199, has P. luteo-album. Fries thinks he had a perichæna on hand; at any rate, not a physarum, and makes Schumacher's combination a synonym for Perichaena quercina Fr., which Rostafinski in turn makes synonymous with P. corticalis (Batsch) R. If "once a synonym always a synonym" be esteemed good taxonomic law, this species must one day have another name. The present author, unwilling to change his colleague's preference in this case, nevertheless begs to suggest that such a binomial as P. listeri would probably at once make future history of the species less eventful, and honor the memory of England's latest and most distinguished student of the group he loved.[Pg 72]

28. Physarum nucleatum Rex.

• 1891. Physarum nucleatum Rex., Proc. Phil. Acad., p. 389.

Sporangia gregarious, spherical, ½ mm., white, stipitate; peridial wall membranaceous, rupturing irregularly, thickly studded with rounded white lime-granules; stipe about 1 mm., subulate, yellowish-white, rugose; columella none, capillitium dense, snow-white, with minute, white, round or rounded nodes, in the centre a conspicuous mass of lime forming a shining ball, not part of the stipe although sometimes produced toward it; spore-mass black; spores brown-violet, delicately spinulose, 6–7 µ.

This species most nearly resembles in appearance and habit of growth P. globuliferum Pers., but may be distinguished from it by the absence of a columella, by the central ball of lime, and the very small rounded lime-granules in the meshes of the capillitium. Exceptionally the lime granules of the sporangium wall are sparse or absent entirely, in which case the wall has a silvery or coppery metallic lustre.

Pennsylvania, Nicaragua.

29. Physarum wingatense nom. nov.

Plate XVI., Figs. 3, and 9.

• 1876. Tilmadoche columbina (Berk. & C.) Rost., Mon., App., p. 13 (?).
• 1889. Tilmadoche compacta Wing., Proc. Acad. Nat. Sci., p. 48.
• 1894. Physarum compactum List., Mycetozoa, p. 45.
• 1896. Physarum compactum (Wing.) Morg., Jour. Cin. Soc., p. 91.
• 1899. Tilmadoche compacta Wing., Macbr., N. A. S., p. 61.
• 1916. Physarum columbinum (Rost.) Sturg., Mycologia, Vol. VIII., p. 4.

Sporangia gregarious, or somewhat crowded, erect or cernuous, stipitate, gray or brownish gray, globose; peridium thin, metallic brown or bronze in color, splitting at maturity in floriform manner into six to twelve segments; stipe white or yellowish white, often shading to black or fuscous below, rather long, tapering upward; hypothallus none; columella none; capillitium extremely delicate, white or colorless, radiating from a central lime-mass or nucleus, and with ordinary nodules small and few, fusiform; spore-mass[Pg 73] brown; spores by transmitted light, violet-brown, delicately warted, 7–8 µ.

This species is well marked by several characteristics; the brilliant wall of the peridium, white-flecked and laciniate, the delicate Didymium-like capillitium running from centre to peridium, and especially the peculiar aggregation of lime at the center of the sporangium, like nothing else except a similar structure found in Physarum nucleatum Rex. The variations affect the stipe and the distribution of the capillitial lime. Some eastern specimens show stipes melanopodous, black below; specimens from Ohio and Nicaragua show stipes milk-white throughout. As to the capillitium, in some of the Nicaragua collections the lime is more uniformly distributed through the capillitium, and accordingly the nucleus is not conspicuous, its place being taken by two or three nodes plainly larger than the others. The peculiar brown metallic lustre of the peridial wall, and the strongly developed calcareous patches with which the peridium is covered are constant features.

That this is the Didymium columbinum Berk., or T. columbina (Berk.) Rost., is very doubtful; the specific name given by Wingate becomes inapplicable when the series is transferred to Physarum, since in that genus the combination is already a synonym. See P. compactum Ehrenberg, Syl. Myc. Berl., p. 21 (1818), cited repeatedly in the synonymy; Fries, op. cit., Vol. III., p. 101. So also P. columbinum, l. c., pp. 133, 135, etc., to say nothing of the fate of Persoon's first record, Obs. Mycol. pars prim., p. 5, 1796. This is Wingate's species, let it bear his name.

30. Physarum newtoni Macbr.

Plate XIV., Figs. 5, 5 a, 5 b.

• 1893. Physarum newtoni Macbr., Bull. Lab. Nat. Hist. Iowa, II., p. 390.
• 1899. Physarum newtoni Macbr., N. A. S., p. 37.
• 1911. Physarum newtoni Macbr., Lister, Mycetozoa, 2nd ed., p. 54.

Sporangia simple, gregarious, short-stipitate or sessile, globulose or flattened, when not globose, depressed and deeply umbilicate above, purple, smooth, thin-walled, stipe when present very short and concolorous; columella none; hypothallus none; capillitium abundant,[Pg 74] delicate, with more or less well-developed nodules, which are also concolorous; spores by transmitted light, dark brown, thick-walled, rough, nucleated, about 10 µ.

A very handsome little species collected by Professor G. W. Newton in Colorado, at an altitude of several thousand feet. Easily recognized by its almost sessile, rose purple, generally umbilicate sporangium.

31. Physarum psittacinum Ditm.

• 1817. Physarum psittacinum Ditm., Sturm, Deutsch. Fl. Pilze, p. 125.
• 1829. Physarum psittacinum Ditm., Fries, Syst. Myc., III., p. 134.
• 1873. Physarum psittacinum Ditm., Rost., Mon., p. 104.
• 1911. Physarum psittacinum Ditm., Lister, Mycetozoa, 2nd ed., p. 55.

Sporangia scattered or gregarious, globose or depressed-globose, or reniform, iridescent-blue, mottled with various tints, red, orange, yellow, white, stipitate; stipe equal, or tapering slightly upward, rugose, orange or orange red, without lime, rising from a small concolorous hypothallus; columella none; capillitium dense, crowded with calcareous, brilliant orange nodules which are angular in outline and tend to aggregate at the centre of the sporangium; spore-mass brown; spores by transmitted light, pale brown, slightly but plainly warted, about 10 µ. N. A. F., 2492.

Differs from P. pulcherripes Pk. in external coloration, the peridium a rich blue, mottled but not with lime; in the capillitium, dense, calcareous, with large angular or branching nodes; in the stipe without lime; in the spores, a little larger than in P. pulcherripes, and by transmitted light much more distinctly brown in color. The sporangia are also broader in the present species, reaching 1 mm.

Rare. Maine, New York, Massachusetts, Pennsylvania. Reported common in Europe, Ceylon, Japan, etc.

32. Physarum discoidale Macbr. n. s.

Plate XX., Figs. 3 and 3 a.

Sporangia gregarious, scattered, discoidal, depressed or umbilicate above, sometimes almost annulate, snow-white, small, .5–.7 mm., stipitate; stipe about twice the sporangium, pale yellow, strand-like,[Pg 75] but erect, even; hypothallus none; columella none; capillitium strongly calcareous, almost as in Badhamia, aggregate at the center, and forming a pseudo-columella at the base of the peridium; peridial wall firm, covered with innate patches of lime, somewhat yellow at the base; spores minutely spinulose, violaceous, 7–9 µ.

This little species reaches us from California. It appears in late winter in undisturbed grass tufts and the sporangia are scattered over the lower leaves. It displays a remarkable amount of lime. The nodules, however, are not large; they are rounded and connected here and there by the ordinary retal tubules characteristic of a physarum.

33. Physarum leucophæum Fr.

• 1818. Physarum leucophaeum Fr., Symb. Gast., p. 24.
• 1875. Physarum leucophaeum Fr., Rost., Mon., p. 113, Figs. 77, 78.
• 1899. Physarum leucophaeum Fr., Macbr., N. A. S., p. 21.
• 1911. Physarum nutans Pers., sub-species leucophaeum (Fr.) Lister, Mycet., 2nd ed., p. 67.

Sporangia scattered or gregarious, stipitate; the peridium globose or sub-depressed, plano-convex, but never umbilicate below, erect, bluish-ashen; the stipe short, rugose, sub-sulcate, fuscous, brown, or sometimes almost white, even or slightly attenuate upward from a thickened base or sometimes from an indistinct hypothallus; capillitium dense, intricate; the nodules white, with comparatively little lime, thin, expanded, angular or branching; columella none; spore-mass black, spores violaceous, minutely roughened, about 8–10 µ.

This extremely delicate and beautiful form is certainly not to be referred to Tilmadoche alba (Bull.) Fr. Fries, who seems to have known of P. compressum A. & S. and refers it to P. nutans Pers., op. cit., p. 130, annotates the present species: "Species especially remarkable in the stipe, in the internal structure, and in its whole habit, nor is there any other with which it may be compared. Peridium thin, not uniform, presently breaking up into laciniate scales; at first yellow, then bluish-ashen; when empty, white. The form inconstant, globose, depressed, but never umbilicate at the base." If we may judge by what Fries says on the subject, he certainly distinguished clearly between this species and T. alba (Bull.), to say[Pg 76] nothing of the stouter, larger, in every way coarser forms called by Rostafinski P. nefroideum, P. compressum, P. lividum, etc.

The shadowy little species has had an eventful history, dipping in and out of our story in most uncertain fashion. Beginning with Fries, as noted, it received confirmation at the hands of DeBary, and by Rostafinski was given priority over a long list of synonyms, and figured. The earlier English authors follow Rostafinski, but for Lister in the Mycetozoa, p. 51, the species becomes a synonym of T. alba as P. nutans, the description appropriately enlarged to receive it. Meantime American students generally confused it with the tilmadoches on the one hand and P. nefroideum R. (supposed) on the other. In 1897, Robt. Fries in Sver. Myxom. Flora, brings the species again to view as co-partner with P. nutans and in the Mycetozoa, 2nd ed., p. 67, it appears as sub-species to the same.

The resemblance to P. album or P. nutans, is chiefly as intimated, a matter of definition; real differences are found in the irregular capillitium, fitting a globose sporange, in the character of the stipe and the consequent pose. See under P. nutans and P. notabile.

34. Physarum nodulosum Cke. & Balf.

• 1881. Physarum nodulosum Cke. & Balf., Rav. N. A. F., Exsic., 479.
• 1889. Badhamia nodulosa Massee, Jour. Myc., Vol. V., p. 186.
• 1891. Physarum calidris Lister, Jour. Bot., Vol. XXIX., p. 258.
• 1896. Craterium nodulosum (Cke. & Balf.) Morg., Jour. Cin. Soc., p. 87.
• 1899. Physarum nodulosum Cke. & Balf., Macbr., N. A. S., p. 51.
• 1911. Physarum pusillum List., Mycetozoa, 2nd ed., p. 64.

Sporangia gregarious; minute, globose, bluish-white, the sporangial wall thin and more or less encrusted with lime, breaking up irregularly, stipitate; stipe slender, longer than the sporangium, attenuate upward or even, bright brown, rugose, expanded above into a shallow cup-like base for the sporangium; columella none; capillitium with lime-knots more or less abundant, white, often uniting, badhamioid; spore-mass black; spores by transmitted light, pale lilac-brown, almost smooth, 10–12 µ.

Pennsylvania, Ohio, Iowa; Canada.

One of the smallest species of the genus, by its proportionally long stipe and small round sporangium reminding one somewhat of P.[Pg 77] globuliferum; much smaller, however, and in every way different. The generic characters are mixed, and the species has been accordingly variously referred. The lower part of the peridium is sometimes persistent after the dehiscence, and so far reminds of Craterium. But this character is not constant, and even at best the persisting part is very small, not greater than in P. melleum, for example. On the other hand, the capillitium in some sporangia is strongly calcareous, reminds of Badhamia, but in most sporangia the Physarum characters are sufficiently clear.

In the Kew Herbarium, it is said, are two American specimens under one label, "Didymium pusillum." One specimen is a didymium indeed, but, as it appears, D. proximum Berk., already described. The other is a physarum. It is proposed in Mycetozoa, 2nd ed., to use the combination thus set free, as if applied by the original author to the second specimen, not didymium, and to make the new combination date from 1873 and so take precedence of the binomial applied in 1881 by Cooke and Balfour here retained by the law of priority.

35. Physarum maculatum Macbr.

Plate XIV., Figs. 6, 6 a, 6 b.

• 1893. Bull. Lab. Nat. Hist. Iowa, II., p. 383.
• 1899. Physarum maculatum Macbr., N. A. S., p. 47.
• 1911. Physarum tenerum Rex., Lister, Mycetozoa, p. 52, in part.

Sporangia scattered or gregarious, very small, .3–.4 mm., dull gray, thin-walled, dotted with minute, white calcareous granules, stipitate; stipe long, about 2 mm., stout, attenuated upward, striate longitudinally or wrinkled, filled with irregular yellow masses of lime and accordingly bright yellow in color; columella none; capillitium forming a dense net, with comparatively small yellow nodular thickenings; spores globose, purplish, each minutely papillose and displaying several scattered spots occasioned by local development of the papillae; diameter of the spores 9–10 µ.

This species was set up for the reception of certain material collected by Professor Shimek, in 1892, in Nicaragua. It remains so far unique. The small globose sporangium mounted upon a long upwardly tapering stipe, .5 mm. thick below, but narrowed at the extreme[Pg 78] base where it is lightly attached, a stem which is simply a sack stuffed with yellow lime-granules;—this and the yellow capillitium are distinguishing features. The capillitium and spores suggest Tilmadoche viride, but the entire habit precludes such reference. Perhaps nearest to P. melleum.

Castillo, Nicaragua.

Miss Lister thinks this the same as P. tenerum Rex. But the whole habit and external appearance are different; the stipe notably long, clumsy, surcharged with lime; a very singular form.

36. Physarum didermoides (Pers.) Rost.

Plate IX., Figs. 1, 1 a, 1 b, 1 c.

• 1801. Spumaria (?) didermoides Acharius, Pers., Syn. Fung., p. xxix.
• 1829. Diderma oblongum Fr., Syst. Myc., III., p. 103.
• 1831. Spumaria licheniformis Schw., N. A. F., p. 261, No. 2364.
• 1832. Physarum atrum Schw., Syn. Fung., Am. Bor., p. 258.
• 1875. Physarum lividum, Schw., Rostafinski, Mon., p. 96.
• 1875. Physarum didermoides (Ach.) Rost., Mon., p. 97.

Plasmodium pale, watery-white or gray; sporangia crowded, ovoid or cylindric, stipitate or sessile, blue-gray, often capped with white; stipe variable in length and structure, where well developed pure white, often flattened, expanded and diaphanous, connate with others through the irregular reticulate or sheet-like hypothallus; columella none; capillitium ample, the lime knots angular or rounded, white connected by hyaline threads; spores in mass black, by transmitted light dark violet, decidedly spinulose, 12–15 µ.

A very variable species in many particulars. The sporangia in the same cluster are stipitate and sessile, ovoid and spherical. Our description does not quite agree with that of Rostafinski. As may be seen from the plate, it is the outer peridium that is with us white, burdened with lime, the inner is simpler and comparatively thin. The whiteness of the outer peridium is however, easily displaced. The colony may not show it at all, in which case the peridia remaining give to the fructification entire a pale lead color, very characteristic. The disposition of the lime in the capillitium is also notably variable. Specimens occur which in so far realize Rostafinski's Crateriachea; that is, the lime is massed as a snow-white pseudo-columella[Pg 79] in the centre of each sporangium. In such cases the lime of the outer peridium is scant or limited in amount, never forming the calcareous cap shown in Fig. 1. The size of the spores is also variable. Rostafinski gives 12.5–14.2 µ; not infrequently a single spore reaches 16 µ, a very unusual range of variation.

The species is not common in the upper Mississippi valley, but can be obtained in quantity where once it appears, as the plasmodia are profuse.

Ohio, Carolinas, Tennessee, Iowa, South Dakota, Kansas. Especially to be looked for on the bark of fallen stems of Populus and Negundo.

Brazil, India, Japan.

Physarum lividum Rost., Mon., p. 95, is but a less calcareous form of this, as is evident even by the author's description. Professor Morgan thought P. lividum a phase of P. griseum Lk. Link, however, reckons P. griseum the same as P. cinereum. Link, Diss., I., p. 27.

37. Physarum leucopus Link.

Plate IX., Figs. 7, 7 a, 7 b.

• 1809. Physarum leucopus Link, Diss., I, p. 27.

Sporangia gregarious, stipitate, globose snow-white, with a didymium like covering of calcareous particles; stipe white, not long, conical or tapering rapidly upward, slightly sulcate, brittle, from an evanescent hypothallus; columella none or small; capillitium, consisting of rather long hyaline threads, connecting the usual calcareous nodes, which are large, angular, snow-white; spore-mass black; spores by transmitted light, violet-brown, distinctly warted, about 10 µ.

The snow-white, nearly smooth stem, the small sporangium (½ mm.) covered with loose calcareous granules, distinguish this rare species. It looks like a small Didymium squamulosum. Fries called it D. leucopus, Syst. Myc., III., p. 121.

Rare. Iowa, Ohio, Maine; Portugal.[Pg 80]

38. Physarum compressum Alb. & Schw.

Plate XVIII., Fig. 14, and Plate XIX., Fig. 12 and Fig. 4.

• 1805. Physarum compressum Alb. & Schw., Fung. Lus., p. 97.
• 1875. Physarum nefroideum Rost., Mon., p. 93, in part.
• 1875. Physarum affine Rost., Mon., p. 94.
• 1909. Physarum compressum Alb. & Schw., Torrend, Fl. des Myx., p. 197.
• 1911. Physarum compressum List., Mycetozoa, 2nd ed., p. 70.

Sporangia more or less scattered, compressed-globose, or compressed-reniform, i. e. often umbilicate, stipitate, sessile, or elongate as if plasmodiocarpous, calcareous, white or ashen; peridium thin, covered with squamules, opening irregularly, usually by apical cleft; stipe, when present, short, stout, more or less sulcate, dark brown or ashen; capillitium a rather loose net, the nodules white, variable in size and shape; spores purplish-brown, delicately roughened, about 10–12.5 µ.

P. affine R. was in this connection set up for European types compressed indeed, but more strongly reniform. The author says in his further description that the form affine is less definitely umbilicate, has white stems, etc.; allantoid, one would now say. Such forms now begin to appear in America; and if for these a specific name is needed, it is provided, P. affine Rost., Plate XIX., Fig. 4.

This seems to be a cosmopolitan species, now that we have found it. However, in North America it is rare. It is reported from Pennsylvania, from Colorado; Harkness found it in California, and the writer has often collected it in Oregon, on Mt. Rainier, Washington, and in California. Europe.

39. Physarum notabile nom. nov.

Plate IX., Figs. 2, 2 a, 2 b; Plate XV., Fig. 2; and Frontispiece.

• 1873. Didymium connatum Peck, Rep. N. Y. Mus., XXVI., p. 74.
• 1879. Physarum polymorphum (Mont.) Rost., Peck, Rep. N. Y. Mus., XXXI., p. 55.
• 1893. Physarum leucophaeum Fr., Ellis, N. A. F., No. 2396, second exhibit.
• 1893. Physarum leucophaeum Fries, Macbr., Bull. Lab. Nat. Hist. Iowa, II., p. 156.
• 1894. Physarum compressum Alb. & Schw., List., Mycetozoa, p. 53, in part.
• 1896. Physarum connexum Link., Morg., Jour. Cin. Soc., p. 92, in part.
• 1896. Physarum confluens Pers., Morg., l. c., p. 94.
• 1899. Physarum nefroideum Rost., Macbr., N. A. S., p. 41, in part.
• 1911. Physarum connatum Lister, Mycetozoa, 2nd ed., p. 71.

[Pg 81]

Sporangia gregarious, sessile, stipitate, or even plasmodiocarpous; when stipitate, depressed, varying at times to irregular reniform in the same colony; globose, the peridium strongly calcareous, cinereous-white; stipe variable, generally tapering upward, always distinctly deeply plicate-furrowed throughout, in color dark, opaque, sometimes touched with white or gray; capillitium abundant, the white lime-knots, varying in size and shape, connected by rather long hyaline threads, with here and there an empty node; spore-mass black, by transmitted light, dark, sooty brown, minutely papillose, 10–11.5 µ.

This remarkable species, while not at all difficult of recognition to one familiar with its phases, is withal very difficult to define. Normally stipitate, it often shows from the same plasmodium all sorts of forms, the shape of the fructification dependent apparently upon external conditions prevalent at the time. The amount of calcium also varies, especially in the capillitium, where there is usually much, with a tendency to the formation of something like a pseudo-columella; the outer net in such cases nearly destitute. The calcium in the stipe also varies; the black or brown stipes are, of course, free from it; the gray or white, calcareous.

In this large and difficult genus, since spore-color is receiving increased consideration,—see No. 31 preceding,—it is proper to note that in the present case two types appear, one with spore-color under the lens, as described, the other with spores violaceous with no trace of black; unshadowed.

The preceding description is based on material assembled during forty years. The form is easily discoverable by any collector throughout the entire valley of the Mississippi and eastward to Nova Scotia. For its naming, students in America have vainly waited the decision of those having access to mycologic types in Europe. It seems now certain that the species is extremely rare in the old world if there occurrent; never seen by any of the earlier taxonomists including Fries and Rostafinski; perhaps adventitious in these later years, although thus far no specimen from Europe has reached this table.[24] P. nefroideum of Strasburg herbarium turns out, after all, teste Lister, to be P. compressum Alb. & Schw., which accordingly shall now enjoy[Pg 82] state and station of its own; our concern in European nomenclature, in the present instance, almost disappears, and we return to our synonymy from this side of the sea.

Mr. Lister would recur to Dr. Peck's Didymium connatum, which indeed represents the present species. In such disposition, how gladly would all concur, were the thing possible! But Physarum connatum is already a synonym twice over.[25] Unless we are done with the rules entirely, P. connatum cannot stand. P. polymorphum and P. leucophaeum are names already in use, of course; and so under the circumstances, much as it is to be regretted, there would seem nothing left to do but to cancel all past synonymy and impose a new name whose permanence may at least be hoped for, if not expected.

40. Physarum tropicale Macbr.

• 1899. Physarum tropicale Macbr., N. A. S., p. 45.

Plate XV., Figs. 4, 4 a, 4 b.

Sporangia scattered, gregarious, turbinate, short stipitate, blue-gray, about 1 mm. in diameter; peridium above iridescent, green, blue, etc., dotted with minute flecks of white, below limeless, purple or bronze shading to the brown of the stipe; stipe short, stout, slightly rugose, cylindric, non-calcareous, brown; columella none; hypothallus none; capillitium abundant, the nodes generally calcareous, small, uniform, angular, white, uniformly distributed; spore-mass, black; spores dark violet-brown, distinctly and closely warted, 12–15 µ.

A large handsome species recognizable by the peculiar turbinate sporangium, with its iridescent peridial wall in which green strongly predominates above, bronze below. The distinction between the upper and lower peridium would suggest Craterium, but the internal structure is not at all Craterium-like. The capillitium is typically of Physarum. The color suggests P. leucophaeum violascens Rost. From this species it is at once distinguished by its much longer sporangia, larger and rougher spores.

Mexico; C. L. Smith: Sure to be again collected once that unhappy country shall again open its forests to research.

[Pg 83]

41. Physarum nicaraguense Macbr.

Plate XV., Figs. 7, 7 a, 7 b; XVII., 11 and 11 a.

• 1893. Physarum nicaraguense Macbr., Bull. Lab. Nat. Hist. Iowa, II., p. 383.
• 1894. Physarum compressum Alb. & Schw., List., Mycetozoa, p. 53, in part.
• 1910. Physarum nicaraguense Macbr., Petch, Mycetozoa Ceylon, p. 334.
• 1911. Physarum reniforme List., Mycetozoa, 2nd ed., p. 72, in part.

Sporangia multilobate or compound-contorted, below obconic, gray, ribbed with calcareous thickenings; stem short, fuscous, longitudinally wrinkled; hypothallus distinct, black; columella none, although the lime massed at the centre of each sporangium simulates one; capillitium white, densely calcareous, with heavy angular nodules connected with comparatively short threads; spores violet, globose, spinulose, about 12 µ in diameter.

Ometepe, Nicaragua. Professor B. Shimek.

This species resembles in some particulars No. 39, especially in the amount of lime present in both capillitium and peridium, in the fluted, sooty stipe, and the rough spores. Mr. Lister once regarded it as the same. Nevertheless, it differs from P. notabile in many definite particulars. In the first place, the sporangia are different in form and habit. They are obconic, nearly always compound, convolute, or botryoid, in this respect somewhat resembling P. polycephalum. Besides, the sporangia are uniformly much smaller, and show constantly the strongly calcified centre, much transcending anything seen in P. notabile. The stipe also is peculiar, quite short, an upward extension or sweep of the common hypothallus which is usually very distinct or prominent; and, while the stipe is longitudinally wrinkled, it is much less so than in the related species, and in a different way. The spores are about the same in size, but differ in color, in this respect agreeing rather with P. leucophaeum.

In the Mycetozoa, 2nd ed., l. c., the present species is entered as a synonym of two described by Massee: Tilmadoche reniformis Mass., Mon., p. 336, and Didymium echinosporum Mass., Mon. 239. But Massee's description of his tilmadoche is, naturally enough, at variance in every important point with the facts in the species before us. Massee says: "... sporangia deeply umbilicate below, sausage-shaped and curved; the stem elongated slender erect, pale brown;[Pg 84] capillitial nodes scattered, fusiform, colorless or yellow; spores 16–17 µ." It is evident that whatever Massee may have had in hand as he wrote it was not P. nicaraguense, which has spores 10–12 µ and reverses the remaining description.

But Didymium echinosporum also defines T. reniformis since Lister, Mon., p. 54, says they are based on two gatherings of one species. Of this second species Massee says: "A superficial resemblance to T. nutans, but distinct in the capillitium which contains no trace of lime; spores 12–14 µ!" Again it is evident that whatever Massee had in hand when he wrote, it was not P. nicaraguense which "has capillitium almost Badhamia-like," i. e., burdened with lime!

Worse than all; Mr. Massee's alleged types are in evidence; one labelled P. reniforme[26] includes forms of P. didermoides and of P. nicaraguense; the other labelled by Berkeley P. nutans is P. nicaraguense. So Mr. T. Petch, Mycet. Ceyl., who enters our species as from Ceylon, and the names cited from Berkeley, Massee, and others, as synonyms. He remarks, "Probably Thwaites' 135 and 55 were mixed during examination"! Doubtless! and some other things too! What Massee did have beneath his lens, no one now may say but apparently not in either case cited, the physarum of Central America.

42. Physarum sulphureum Alb. & Schw.

• 1805. Physarum sulphureum Alb. & Schw., Consp. Fung., p. 93, Tab. VI, f. 1.
• 1818. Physarum flavum Fries, Symb. Gast., p. 22.
• 1875. Physarum sulphureum Alb. & Schw., Rost., Mon., p. 101.[27]

Sporangia gregarious, sub-globose, rugulose-squamulose, .6–.8 mm., sulphur-yellow, stipitate; peridium membranous, covered with calcareous scales; stipe stout, white, charged with lime, furrowed; columella none; capillitium strongly calcareous, the nodules large, white; spores violaceous, rough, 9–11 µ.

Northern Europe. (Lusatia) Lausitz, Alb. & Schw.; dim old[Pg 85] Wendish region on the south borders of Brandenburg. Reported also from Sweden.

The description and figure given by Schweinitz, 1805, l. c., leave no doubt as to what he had in hand. Twenty or thirty years later, having spent the interval in this country,—bishop, indeed, of the Moravian churches, but a student of fungi all the while,—he reports the same thing from this country; Proc. Phil. Acad. Sci., 1834. Cooke also lists it in Myxomycetes of the U. S. It surely will be found again. Mr. Lister thinks P. variable Rex may be the same thing.

43. Physarum carneum G. Lister and Sturgis.

• 1910. Physarum carneum G. Lister and Sturgis, Jour. Bot., Vol. XLVIII, p. 63.

Sporangia gregarious, stipitate, sub-globose, .5 mm. in diameter, ochraceous-yellow above, flesh-colored below; peridium membranous, pale yellow, lime-granules evenly distributed; stipe short, translucent, pinkish flesh-colored; capillitium dense, nodules white; spores purplish-brown, spinulose, 8 µ.

Differs from P. citrinellum in the membranous peridium, flesh-colored stalks and smaller spores.

Colorado; Dr. W. C. Sturgis.

44. Physarum citrinellum Peck.

• 1831. Physarum caespitosum Schw., Syn. N. A. F., No. 2301 (?).
• 1869. Diderma citrinum Peck, Rep. N. Y. Mus., XXII., p. 89.
• 1870. Physarum citrinellum Peck, Rep. N. Y. Mus., XXXI., p. 55.
• 1894. Craterium citrinellum List., Mycetozoa, p. 74.
• 1899. Physarum caespitosum Schw., Macbr., N. A. S., p. 37.
• 1911. Physarum citrinellum Peck, List., Mycetozoa, 2nd ed., p. 62.

Sporangia gregarious, or scattered globose, short-stipitate, pale yellow or ochraceous, smooth or slightly roughened by the presence of minute lime-particles; peridium more or less distinctly double, the outer calcareous, fragile, the inner very delicate, with here and there a calcareous thickening, ruptured irregularly; stipe very short, half the sporangium, fuliginous, furrowed, expanded below into an imperfectly[Pg 86] defined hypothallus; capillitium abundant, the nodes stellate-angular, large, the internodes delicate, short; spore-mass black, spores violaceous-brown by transmitted light, strongly spinulose, 10–12.5 µ.

A very distinct and handsome species. Easily recognizable at sight by its large, globose, almost sessile and yet distinctly stalked sporangia. The color to the naked eye is pale ochraceous or buff. Only under a moderate magnification do the citrine tints come out.

In the Twenty-second N. Y. Report, Dr. Peck incorrectly referred this species to Physarum citrinum Schum. On the appearance of Rostafinski's Monograph, Dr. Peck in his revised list, l. c., writes P. citrinellum Peck, with description on p. 57, following. Under the last name the species has been generally recognized in the United States and distributed. N. A. F., 2490.

In the former edition, this species was referred to P. caespitosum Schw., of which the original description is as follows: "P. caespitosum L. v. S., pulcherrimum. In foliis et stipitibus Rhododendri, Bethlehem. Physarum substipitatum aut saltem basi attenuata, caespitosim crescens et sparsim. Caespitulis 3 linearibus; peridiis stipatis, turbinatis, ovatis, basi contracta membranula exterori luteosquamulosa aut punctato-squarrulosa. Sporidiis nigro-brunneis, floccis citrinis inspersis." Synopsis N. A. Fungi, 2301.

The type from the Schweinitz herbarium is no longer in evidence. Without it, the reference cannot be sustained.

Not uncommon in the eastern United States; reported also from Japan.

45. Physarum albescens Ellis.

Plate XVI., Figs. 4, 4 a.

• 1889. Physarum albescens Ellis in litt: not described.
• 1893. Physarum auriscalpium Cke., Macbr., Bull. Lab. N. H. Iowa, No. 2, p. 155, in part.
• 1894. Physarum virescens var. nitens List., Mycetozoa, p. 59, in part.
• 1899. Physarum virescens var. nitens List., Macbr., N. A. S., p. 34, in part.
• 1899. Leocarpus fulvus Macbr., N. A. S., p. 82.
• 1911. Physarum fulvum Lister, Mycet., 2nd ed., p. 60.
• 1911. Physarum virescens, nitens List., Mycet., 2nd ed., p. 84, in part.

[Pg 87]

Sporangia gregarious, scattered, ovoid or globose, pale yellowish or fulvous, opening irregularly above, stipitate; the peridium double, the outer layer more or less calcareous, the inner delicate, almost indistinguishable, persistent below as a shallow cup; the stipe long, weak, striate, fulvous or yellow; hypothallus distinct, venulose, or more or less continuous; capillitium pallid or white, dense, with here and there below large continuous yellow calcareous nodules; columella none; spore-mass black; spores by transmitted light, dark brown, rough, 13–15 µ. Varies to forms with single (inner) peridium and simple physaroid capillitium. Vid. descriptions cited for P. auriscalpium, P. nitens, etc.

This interesting form is from our western mountains, and suggests at first a diderma; but the capillitium is entirely unlike that of a diderma in color and structure, and plainly belongs here. Plasmodium yellow, on fallen leaves and twigs. Our material is from Prof. Bethel, Denver; and Lake Tahoe, Nevada; later from Dr. Weir, Montana. No doubt common at high altitudes near the snow-line in mountainous regions, probably around the world.

As indicated above, this was originally entered as of the genus Leocarpus; the taxonomic history of the form may interest readers who note with surprise the presentation in synonymy here developed.

About thirty-five or forty years ago Dr. Harkness of California sent to Mr. Ellis of New Jersey a slime-mould which the sender referred to Diderma albescens Phillips, (Grev. V., p. 114, 1877). Ellis sent a small bit to the Iowa herbarium without other comment, save that he thought it a physarum. Sometime later Mr. Ellis received from Father Langlois, a correspondent in Louisiana, specimens he esteemed the same thing. He expressed the opinion that if this were what Phillips had found in California, it should perhaps be called a physarum. The Louisiana material by his courtesy came also to this table. The material was scanty, in poor condition, and all waited further light. To these specimens the writer paid less attention. They were in the hands of his correspondents and the courtesy of the case required their further consideration by Dr. Rex.

In 1889 Mr. Holway found in Iowa, a physarum of which he sent part to Ellis and the remainder to the writer who, then engaged on the Myxomycetes of East. Iowa, referred his part of this Iowa gathering[Pg 88] to the Physarum auriscalpium Cke. as found in New York. Under this caption a specimen was later sent to Mr. Lister, who has, as we see, consistently regarded the thing as a variety of P. virescens Ditmar, P. nitens List.

Meantime in 1898 Colorado material from Professor Bethel reached the University. This did not recall any of the materials sent from Ellis. Diderma albescens had meanwhile come again from California, and been recognized as Diderma niveum Rost.

Accordingly, in N. A. S. the latest arrival from Colorado was described as a new species, and with some temerity perhaps, offered as a second species of the hitherto monotypic Leocarpus, all on account of the peculiar capillitium. Sometime after publication our most valued correspondent Mr. Bilgram called attention to the resemblance between the Colorado and Louisiana material already referred to. The University specimens as stated were small, broken, and in every way poor, but enough remained to indicate the evident justice of our correspondent's suspicion. Further investigation of the Holway material in Philadelphia showed that it too was entitled to consideration! Inasmuch as the Holway sending was all from one plasmodium, all difficulties vanished at once. The Iowa gathering showed two phases: one at the University represents P. nitens, physaroid, single-walled; while the Philadelphia part of the gathering corresponds, poorly it is true, but in fact, as now appears, to the form coming in perfection from Colorado; leocarpine in structure, published as Leocarpus fulvus; P. fulvum Lister. Since the combination P. fulvum is already in use, synonym of P. rubiginosum, it seems better to write the name suggested by Ellis; Physarum albescens never having been published, because Diderma albescens, as noted took care of itself.

Since Rostafinski we separate all these physaroid forms chiefly by capillitial characters: capillitial structure separates genera. Physarum diderma is a physarum despite its double wall. And so here Leocarpus was set out by its differentiating capillitium. In good specimens of the present species a large part of the capillitial net is entirely free from lime, so that when the peridium first opens at the summit, sometimes no trace of lime appears; the calcareous deposits are below, and tend to occupy not the nodal intersections as in[Pg 89] Physarum, but in large masses involve portions of the net itself, nodes and all, as in Leocarpus. Miss Lister's beautiful figures, op. cit., Figs. 66 and 82, show this very well.

In The Journal of Botany, 52, p. 100, the distinguished author and artist records the discovery of this species in the mountains of Switzerland. She says: "This specimen shows a striking resemblance to Leocarpus fragilis Rost., both in the shape of the sporangia and in the capillitium and spores; but although the color of the sporangia varies in both these species, the walls of P. (L.) fulvum are membranous and rugose with included deposits of lime granules and show nothing of the polished cartilaginous layers characteristic of L. fragilis."

The species is a boundary type at best, and shows again how artificial all our taxonomy is apt to prove, when the number of presentations of some particular type becomes larger.

For these reasons, the present author writes Physarum, and believes the question of identity in a perplexing case fortunately settled.

46. Physarum variabile Rex.

• 1893. Physarum variabile Rex, Proc. Phil. Acad., p. 371.
• 1911. Physarum variabile Rex, List., Mycetozoa, 2nd ed., p. 47.

Sporangia scattered, stipitate, sub-stipitate or sessile, about 1 mm. high; regularly or irregularly globose, ellipsoidal, obovate or cylindric-clavate in shape; sporangium wall sometimes apparently thick, of a dingy yellow or brownish-ochre color, slightly rugulose on the surface, crustaceous, brittle, rupturing irregularly, sometimes thin, translucent, covered externally with flat circular calcic-masses falling away in patches; stipes nearly equal, occasionally much expanded at the base, rough, longitudinally rugose, variable in size, sometimes one-third of a millimetre high, sometimes a mere plasmodic thickening of the base of the sporangium; color of stipes varying from a yellowish-white to a dull brownish-gray; capillitium a small-meshed network of delicate colorless tubules with large, many-angled, rounded masses of white, or rarely yellowish-white lime-granules at the nodes; no true columella, but often a central irregular mass of white lime-granules; spores dark violet-brown, verruculose, 9–10 µ.[Pg 90]

Pennsylvania. Dr. Rex.

Lister, op. cit., describes a variety, sessile, presenting plasmodiocarpous fructification, from Ceylon, also from Antigua, but there are some doubts as to the identity of these with American sessile and plasmodiocarpous forms. Vid. Jour. Bot. XXXVI., p. 113.

47. Physarum auriscalpium Cooke.

• 1877. Physarum auriscalpium Cooke, Myx. U. S., Am. Lyc. Nat. Hist. N. Y., XI., p. 384.
• 1877. Physarum auriscalpium Cke., Myx. Gr. Brit., Pl. 24, f. 253–4.
• 1893. Physarum sulphureum (Alb. & Schw.), Sturgis, Bot. Gaz., XVIII., p. 197.
• 1898. Physarum auriscalpium Cke., List., Jour. Bot., XXXVI., p. 115.
• 1911. Physarum auriscalpium Cke., List., Mycetozoa, 2nd ed., Syn. excl.

Sporangia scattered, stipitate or occasionally sub-sessile spherical, .8–1 mm. high; peridium granulated, bright golden yellow; stipe, when present, one-half to two-thirds the height of the sporangium, blackish-brown; hypothallus, minute, thin, brown; columella absent; capillitium rather dense, composed of large angular nodes, completely filled with bright yellow granules of lime, and connected by very short, delicate, colorless internodes destitute of lime; spores globose minutely verruculose, or asperate, 10.7–11.8 µ in diameter, brownish-violet by transmitted light, black in the mass.

This is the original description, 1893, of P. sulphureum (Alb. & Schw.) Sturgis; the author last named having compared certain stalked New England forms with what he could find of P. sulphureum in the herbarium of Schweinitz at Philadelphia, and having, as he thought, established identity.

Meantime Mr. Lister had been inclined to refer P. auriscalpium Cke. to P. rubiginosum Fr., Mycetozoa, p. 61.

In 1898 Professor Sturgis and Mr. Lister agreed that the New England specimens, owing to color and character of stipe and some other differences could not be the Schweinitzian species, but did indeed conform much better with those in London labelled P. auriscalpium Cke.

Accordingly P. sulphureum is something else, very different, (v.[Pg 91] A. & S., Cons. Fung. Tab., VI., f. 1), and by aid of recent[28] discoveries in Sweden goes its own way again. Meanwhile P. sulphureum Sturgis stands, a new type for P. auriscalpium Cke., the description modified to suit; the lamented pioneer-author receives honor due, and his handsome species, with its "golden graving," may now march, let us hope, under appropriate banner far down the fair highway to future fame!

48. Physarum oblatum Macbr.

Plate III., Fig. 6; Plate XIV., Figs. 3, 3 a, 3 b.

• 1879. Physarum ornatum Peck, Rep. N. Y. Museum, XXXI., p. 40 (?).
• 1893. Physarum oblatum Macbr., Bull. Lab. Nat. Hist. Iowa, II., p. 384.
• 1896. Craterium maydis Morg., Myx. Miam. Vall., p. 87.
• 1909. Physarum maydis Torr., Flor. des Myxo., p. 193.
• 1911. Physarum maydis Torr. List., Mycet., 2nd ed., p. 59.

Sporangia gregarious, stipitate, small, bright yellow, globose or depressed-globose, rough; stipe reddish-brown or fuliginous, even, short, slender; hypothallus scant, black, or none; columella none; threads of the capillitium yellow, delicate, connecting the rather dense and abundant yellow lime-granules; spore-mass brownish-black, spores violaceous, minutely but distinctly spinulose, 9–11 µ.

This species is easily recognizable by its brilliant yellow color, somewhat rugose, sometimes scaly peridium, its richly calcareous capillitium, also bright yellow where not weathered or faded, its dark brown, translucent, non-calcareous stem. In dehiscence, the base of the peridium in cup-form, sometimes persists. This circumstance, with the fact that decaying maize-stalks and leaves are a favorite habitat, led Professor Morgan to its description as Craterium maydis. But it is doubtless a physarum, occurring on habitats of all sorts, from Ohio to Iowa, Colorado and Washington. Ceylon(?).

Physarum ornatum Peck is doubtfully cited here, although Professor Morgan thought it the same as P. oblatum. As a matter of fact the original brief description, op. cit., does not suggest either P. oblatum or P. maydis; rather a form of Tilmadoche viridis. Professor[Pg 92] Sturgis, Notes on Some Type Specimens of Myxo., in the N. Y. Museum, Trans. Conn. Acad. Arts and Sci., Vol. X., Pt. 2, p. 470, says that of the type almost nothing remains, that the name P. ornatum Pk. "should be discarded."

49. Physarum galbeum Wing.

• 1890. Physarum galbeum Wing., Ell., N. A. F., 2491 (no description).
• 1892. Physarum petersii Berk. & C., Mass., Mon., p. 296, in part.
• 1894. Physarum berkeleyi Rost., List., Mycetozoa, p. 48, in part.
• 1899. Physarum galbeum Wing., Macbr., N. A. S., p. 53.
• 1911. Physarum galbeum Wing., List., Mycetozoa, 2nd ed., p. 59.

Sporangia scattered, globose, stipitate, often nodding, golden yellow, the peridium exceedingly thin, breaking up into patches on which the yellow lime granules are conspicuous; stipe non-calcareous, pale brown or amber-colored, longitudinally wrinkled, about one and one-half times the diameter of the peridium; columella none; hypothallus none; capillitium dense, extremely delicate, the nodes only here and there calcareous, the lime knots when present small, angular, yellow; spore-mass pale brown; spores almost smooth, lilac- or violet-tinted, 7.5–10 µ.

Distinguished among the small delicate species with which it will be naturally associated, by the yellow, richly calcareous wall of the globose sporangium and the almost limeless capillitium. The stipe is hollow and contains irregular masses of refuse granular matter, but no lime so far as we have been able to discover. P. flavicomum, to which the species is related most closely, differs in having the wall non-calcareous, iridescent, as well as in the color throughout; the character of the capillitium, in which lime is abundant; the absence of refuse-matter in the stem.

Pennsylvania, Iowa, Minnesota.

50. Physarum tenerum Rex.

• 1890. Physarum tenerum Rex., Proc. Phil. Acad., p. 192.
• 1894. Physarum polymorphum Rost. var. obrusseum, Lister, Mycet., p. 48.
• 1899. Physarum obrusseum (Berk. & C.) Rost., Macbr., N. A. S., p. 52.
• 1911. Physarum tenerum Rex., List., Mycetozoa, 2nd ed., p. 52.

[Pg 93]

The peridium thin, membranaceous, thickly studded with circular, flattened, yellow granules of lime; stipe long, slender, subulate, opaque, pale brown, striate and black below, pale yellow above; columella none; capillitium yellow or white, delicate, forming a loosely but regularly meshed network with numerous small round or rounded granules at the intersections; spores dark brown, delicately warted, 7–8 µ.

This delicate physarum, very fragile and evanescent, seems to be distinct, by reason of its characteristic rounded lime granules, from any similar, stipitate species. It varies a little according to locality. Ohio specimens are a little larger and have thicker and more calcareous stipes than is usual in those from Philadelphia. The walls of the sporangia when fully matured generally break into several petal-like segments which finally become reflexed. The description given by Berkeley is entirely insufficient.

In an earlier edition this species was entered as P. obrusseum following the Polish text. Miss Lister who has the type of Didymium obrusseum at hand considers it as representing a phase of Physarum polycephalum Schw. D. tenerrimum Berk. & Curt. is judged the same. P. tenerum Rex is, in any event, certain, and the combination is adopted.

Rare:—Pennsylvania, Ohio, Louisiana, Texas, Iowa, Portugal, Japan.

51. Physarum flavicomum Berk.

Plate XV., Figs. 3, 3 a.

• 1845. Physarum flavicomum Berk., Hook. Jour. Bot., IV., p. 66.
• 1873. Physarum cupripes, Berk. & Rav., Grev., II., p. 65.
• 1875. Physarum berkeleyi Rost., Mon., p. 105.
• 1894. Physarum berkeleyi Rost., List., Mycetozoa, p. 57.
• 1899. Physarum flavicomum Berk., Macbr., N. A. S., p. 53.
• 1911. Physarum flavicomum Berk., List., Mycetozoa, 2nd ed., p. 58.

Sporangia gregarious, small, spherical, at first fuliginous throughout, stipitate; the peridium thin, destitute of lime, iridescent, breaking up and deciduous in patches, except at the base; stipe twice the diameter of the peridium, brown, fluted, not hollow, tapering upward from a small but distinct, radiant hypothallus; columella none;[Pg 94] capillitium dense, persistent, the nodes frequently calcareous, elongate and vertical, especially below, yellow; spore-mass brown; spores by transmitted light, bright violaceous-brown, slightly papillose, 9–10 µ.

This species is instantly distinguishable from all cognate forms by its peculiar sooty color. Not less is the species structurally marked by its capillitium. The latter below is exactly as in the species of Tilmadoche. Indeed, the present species unites characters supposed to distinguish Physarum from Tilmadoche, and would so far justify those authors who bring all the species of both genera together under one generic name. In any case the species is by its capillitium entirely distinct from P. galbeum, as well as by the structure of the stipe and the peridial surface. The plasmodium, at first watery, emerges from decayed elm logs and soon takes on a peculiar greenish tint preserved somewhat in the mature fruit.

Rostafinski, Monograph, pp. 105, 106, rejects Berkeley's specific name, flavicomum, because it refers to the somewhat indefinite, characteristic color. As this is no valid reason for change, we have restored Berkeley's specific name, which by general consent has priority. N. A. F., 3299.

Not common. New Jersey, Ohio, South Carolina, Iowa.

52. Physarum bethelii (Macbr.) Lister.

• 1899. Tilmadoche bethelii, Macbr., Exempl. ad Herbaria.
• 1911. Physarum gyrosum Rost., List., Mycetozoa, 2nd ed., p. 75.

Sporangia scattered, globose, umbilicate below, .5–1 mm. in diameter, iridescent blue, or sometimes tinged by the presence of delicate pale yellow calcareous scales, stipitate; stipe rather short, black or dark brown, equal; capillitium dense, radiating from the black, slightly intrusive summit of the stipe, and from the base of the peridium ascending; the nodules not numerous, elongate, branching betimes, pale yellow; spores minutely roughened, 10–12 µ.

This beautiful delicately tinted little species is clearly tilmadochoid in the Friesian sense. The capillitium persists after the fall of the upper filmy peridium, adherent below to the persisting peridial base. Collected thus far twice only; by Professor Bethel and by Professor Sturgis, Colorado.[Pg 95]

SECTION 2

Tilmadoche Fries

53. Physarum gyrosum (Rost.) Jahn.

• 1875. Physarum gyrosum Rost., Mon., p. 111.
• 1902. Physarum gyrosum Rost., Jahn, Ber. Deutsch. Bot. Ges., XX., p. 272, t. XIII.
• 1911. Physarum gyrosum Rost., List., Mycetozoa, 2nd ed., p. 75.

Sporangia gyrose, variable in form, or plasmodiocarpous and irregular, venulose, sessile upon a common, strongly developed hypothallus, sometimes isolated and irregularly globose, dehiscing irregularly or by longitudinal fissure, yellowish or greyish white; columella none; capillitium delicate, the nodules elongate, variable in size; spores pale violaceous, minutely spinulose, 7–10 µ.

This is a European species recently resuscitated by Dr. Jahn. It perhaps might more correctly be recorded as P. gyrosum Jahn, since Rostafinski certainly attempted in his description to cover two apparently distinct things. He seems to have had before him Fuligo muscorum Schw. and "P. gyrosum," but he thought them the same, and his description touches now one, now the other. Since F. muscorum Schw. has all along held its own and received due recognition, it is interesting to note the recovery of this gyrose form.

Judging by description and figures, it resembles a very large, sessile phase of P. polycephalum. See further under that species.

Europe, Japan, Eastern United States (?).

54. Physarum polycephalum Schw.

Plate VIII., Figs. 2, 2 a, 2 b.

• 1822. Physarum polycephalum Schw., Syn. Fung. Car., No. 382.
• 1829. Didymium polycephalum (Schw.) Fries, Syst. Myc., III., p. 122.
• 1837. Didymium polymorphum Mont., Ann. Sci. Nat., Ser. 2, 8, p. 361.
• 1837. Didymium gyrocephalum Mont., op. cit., p. 362.
• 1875. Physarum polymorphum (Mont.) Rost., Mon., p. 107.
• 1875. Tilmadoche gyrocephala (Mont.) Rost., Mon., p. 131.
• 1899. Tilmadoche polycephala (Schw.) Macbr., N. A. S., p. 57.
• 1911. Physarum polycephalum Schw., List., Mycetozoa, 2nd ed., p. 58.

[Pg 96]

Sporangia spherical or irregular, impressed, gyrose-confluent, helvelloid, umbilicate below; peridium thin, ashy, covered with evanescent yellow squamules, fragile; stipe from an expanded membranaceous base, long-subulate, yellow; spores smooth, violet, 9–11 µ.

A most singular species and well defined is this, occurring in masses of decaying leaves or on rotten logs. The plasmodium at first colorless; as it emerges for fructification, white, then yellow, spreading far over all adjacent objects, not sparing the leaves and flowers of living plants; at evening slime, spreading, streaming, changing; by morning fruit, a thousand stalked sporangia with their strangely convoluted sculpture. The evening winds again bear off the sooty spores, and naught remains but twisted yellow stems crowned with a pencil of tufted silken hairs. August.

Although Rostafinski's description of this species is accurate and marks exactly a Tilmadoche and is very different from his description of Physarum polymorphum, nevertheless it is probable that both descriptions have reference to the same thing. All specimens on which both species were based were American; P. polymorphum, North American. But the only North American form to which reference can be made is that by Schweinitz called P. polycephalum and, fortunately, sufficiently described. Furthermore, Rostafinski, under T. gyrocephala, himself affirms the probable identity of Montagne's Didymium gyrocephalum with the Schweinitzian species, and uses Montagne's specific name provisionally. For these reasons it seems proper to write the species as above.

Widely distributed and common, from Maine and Canada to Nebraska, and Washington and south to Nicaragua.

This species is so common that its plasmodium and fructification may be easily observed. Professor Morton E. Peck, who has been for years a close observer of the vegetative phases of our Iowa species, says of P. polycephalum: "In one instance I observed a plasmodium for twelve successive days on the surface of a decaying stump. During this period it crept all around the stump and from top to bottom several times. At one time the color was bright yellow; at another, greenish yellow; and once, shortly before fruiting, it became clear bright green. A heavy rain fell upon the plasmodium but it appeared[Pg 97] to sustain little injury and ultimately developed normal sporangia."

55. Physarum nutans Pers.

• 1791. Sphaerocarpus albus Bull., Champ., p. 137, t. 407, III., and t. 470, I, A-L.
• 1791. Stemonitis alba (Bull.), Gmel., Syst. Nat., p. 1469 (?).
• 1795. Physarum nutans Pers., Ust. Ann. Bot., XV., p. 6.
• 1803. Trichia cernua Schum., Enum. Pl, Saell., II., p. 241.
• 1829. Physarum cernuum (Schum.) in part, Fr., Syst. Myc., III., pp. 130, 147.
• 1848. Tilmadoche cernua (Schum.) Fr., Summ. Veg. Sc., p. 454.
• 1873. Tilmadoche nutans (Pers.) Rost., Versuch, p. 10.
• 1899. Tilmadoche alba (Bull.) Macbr., N. A. S., p. 58.
• 1911. Physarum nutans Pers., List., Mycet., 2nd ed., p. 67, in part.

Sporangia gregarious, depressed-spherical, stipitate, umbilicate, gray or white, thin-walled, nodding; stipe long, tapering upward, brown or black below, ashen white above, lightly striate, graceful; capillitium abundant, threads delicate, intricately combined in loose persistent network with occasional minute, rounded, or elongate calcareous nodules; spores minutely roughened, globose, about 10 µ.

The nodding, lenticular, umbilicate sporangium, barely attached to the apiculate stipe, is sufficient to distinguish this elegant little species, recognized and quite aptly characterized by mycologists for more than one hundred years. As Sphaerocarpus albus Bulliard first prescribed the limits by which the species is at present bounded. The description by Fries (Syst. Myc.,, III., 128) is especially graphic; "Peridium very thin, in form quite constantly lenticular, umbilicate at base, at first smooth then uneven, generally laciniate-dehiscent, the segments persistent at least at base."

The stipe is usually white above, fuscous below, at the apex almost evanescent; hence the cernuous sporangia. The same character is less strikingly manifest in the species next following.

The plasmodium is bright yellow, sometimes greenish. Brought in from the field and maturing under a bell-jar, the color changes to a watery white just before the sporangia rise in fruit. P. album Fuckel, Rhen. Fl., No. 1469, 1865, is believed to be P. cinereum (Batsch) Pers.[Pg 98]

Persoon changed Bulliard's specific name in this case to furnish one himself, more descriptive as he thought and distinctive. His success in this attempt must be esteemed but partial since all the related forms, immediately listed, nod as well. Bulliard's name as applied by Persoon is therefore to be preferred. But the transfer from Tilmadoche to Physarum loses for us one step in the ladder of priority. P. album (Bull.) may not enter here, since Fries has given us one species under that title. So Persoon comes next on the list, all the world now nodding approbation, let us hope!

Under the name Physarum gracilentum, Fries cites an extremely delicate form of this species. The sporangia are of the most minute, about .2–.3 mm. in diameter, globose, slightly umbilicate below, the stipe usually white at top, but sometimes black throughout. This graceful form occurs rarely in undisturbed woods.

Widely distributed in the eastern United States, apparently rare in the west. Reported from various parts of the world; Europe, Japan, Australia, etc.

56. Physarum viride (Bull.) Pers.

Plate VIII., Fig. 8, 8 a, 8 b.

• 1791. Sphaerocarpus viridis Bull., Champ., t. 407, Fig. I.
• 1791. Sphaerocarpus luteus Bull., Champ., t. 407, Fig. II.
• 1791. Sphaerocarpus aurantius Bull., Champ., t. 484, Fig. II.
• 1791. Stemonitis viridis (Bull.) Gmel., Sys. Nat., p. 1469.
• 1794. Physarum aureum Pers., Römer, Neu. Mag. f. die Bot., I., p. 88.
• 1795. Physarum viride Pers., Usteri, Ann. Bot., XV., p. 6.
• 1801. Physarum aurantium Pers., Syn. Meth., p. 173.
• 1829. Physarum nutans var. Fries, Syst. Myc., III., pp. 128–129.
• 1875. Tilmadoche mutabilis Rost., Mon., p. 129.
• 1880. Tilmadoche viridis (Bull.) Sacc., Michelia, II., p. 263.
• 1894. Physarum viride Pers., List., Mycetozoa, p. 50.
• 1899. Tilmadoche viridis (Bull.) Sacc., Macbr., N. A. S., p. 59.
• 1911. Physarum viride Pers., List., Mycetozoa, 2nd ed.

Sporangia globose, flattened or lenticular, beneath plane or concave, variously colored, yellow, greenish yellow, rusty orange, stipitate, nodding; the peridium splitting irregularly or reticulately; stipe variable in length and color, through various shades of red and yellow, subulate; capillitium strongly developed, concolorous with sporangium, the tubes with colorless or yellow calcareous thickenings; spores smooth, fuscous or violet-black, 8 µ.[Pg 99]

A very handsome and rather common little species; like the preceding, but generally greenish-yellow in color, and occasionally brilliantly orange without a suggestion of green. Indeed, the color is so variable that some authors have been disposed to discard the species entirely, inasmuch as the chief specific character is color. The plasmodium is pale yellow, in rotten logs, stumps, etc. In the paler yellow or greenish forms the stipe is more commonly black.

This is Physarum luteum (Bull.) Fries, and likewise also includes the three varieties, viride, aureum, coccineum, listed by the same author under P. nutans, while he at the same time remarks that they might with equal propriety be elsewhere referred. Rostafinski considers that all the colored forms agree in capillitium sufficiently to be associated under one name and are in the same way unlike T. nutans.[29] Rostafinski thinks to avoid confusion by suggesting a more fitting specific name, T. mutabilis, but there seems no good reason for not adopting the earliest identifiable specific appellation, which in this case appears to be viride. The yellow phase is common in Iowa, resembles in size, color, stipe, P. galbeum Wingate, but is instantly distinguishable by the capillitium. N. A. F., 1213.

Widely distributed specimens are before us;—from New England, New York, Pennsylvania, Maryland, Ohio, Nebraska, Iowa, California, Oregon, Canada, Nicaragua, Samoa, Alaska, India, etc.

EXTRA-LIMITAL[30]

Physarum mutabile (Rost.) List.

• 1875. Crateriachea mutabilis Rost., Mon., p. 125.
• 1892. Crateriachea mutabilis Rost., Mass., Mon., p. 344.
• 1894. Physarum cinereum List., Mycetozoa, p. 55, in part.
• 1895. Physarum crateriachea List., Jour. Bot., XXXIII., p. 323.
• 1910. Physarum crateriachea List., Petch, Mycetozoa Ceylon, p. 336.
• 1911. Physarum mutabile List., Mycetozoa, 2nd ed., p. 53.

Sporangia cylindrical ovoid or sub-globose white, plasmodiocarpous, sessile or stipitate, stipes when present yellow, with or without lime, often connected by a hypothallus; peridium thin, squamulose; capillitium[Pg 100] persistent, intricate, the nodules white, more or less confluent at the center to form a real or a pseudo-columella; spores brownish-purple, spinulose, 7–8 µ.

Reported from Europe, Africa, Ceylon.

Physarum roseum Berk. & Br.

• 1873. Physarum roseum Berk. & Br., Jour. Linn. Soc., XIV., p. 84.

Plasmodium rose-red; sporangia gregarious, stipitate, globose, rose-red; the stipe erect, brown, rugulose, translucent; capillitium lax, delicate, lilac, the nodules few, large, purple-red, branching; spores reddish-lilac or brown, minutely spinulose, 7–10 µ.

Reported from Ceylon, Java, Borneo, Japan.

Physarum dictyospermum List.

• 1905. Physarum dictyospermum List., Jour. Bot., Vol. XLIII., p. 112.

"It is distinguished from the other known species of Physarum by the strongly reticulated spores. Its nearest ally is perhaps P. psittacinum which it resembles in having orange-red lime-knots and in the sporangium-wall being studded with orange crystalline disks." Lister.

Reported collected once only; New Zealand.

Physarum straminipes List.

• 1898. Physarum straminipes List., Jour. Bot., Vol. XXXVI., p. 163.

Plasmodium white; sporangia greyish-white, obovoid or wedge-shaped, .7 mm. in diameter, clustered or scattered, stipitate or sessile, when stipitate stalks long, weak; peridium membranous, pale purple; capillitium a persistent rigid net, the nodules white, rounded, sometimes aggregate as a pseudo-columella; spores purple-brown, 10–11 µ, warted, the papillae in definite patches.

Related to P. compressum.

Reported from England; Germany.

Physarum crateriforme Petch.

• Physarum crateriforme Petch, Ann. Perad., IV., p. 304.
• Physarum crateriforme Petch, List., Mycetozoa, 2nd ed., p. 69, Pl. 76.

Sporangia gregarious, globose, clavate or crateriform, sessile or[Pg 101] stipitate, white; stalk when present opaque conical, black below, white above, in crateriform sporangia entering and developed as a columella; capillitium various, strongly calcareous, the nodules either grouped in a pseudo-columella, or in globose sporangia, rod-like, ascending; spores closely spinulose, 11–15 µ.

Reported from Ceylon, Japan, West Indies; Lisbon.

Physarum gulielmæ Penzig.

• 1898. Physarum gulielmae Penzig., Myx. Beut., p. 34.
• 1909. Physarum gulielmae Penzig., Torrend, Fl. des Myx., p. 208.
• 1911. Physarum gulielmae Penzig., List., Mycetozoa, 2nd ed., p. 76.

Plasmodium yellow; sporangia sub-globose, sessile, brownish-orange or chestnut brown, rugulose, clustered or heaped, often with a yellow membranous hypothallus; peridium membranous with clustered deposits of yellowish-brown lime granules; capillitium abundant, the nodes angular, branching, white; spores purplish brown, spinulose, 10–12 µ.

Reported from Java, Sweden, Switzerland.

Physarum echinosporum List.

• 1899. Physarum echinosporum List., Jour. Bot., XXXVII., p. 147.

This species is distinguished from the preceding chiefly in episporic characters. "Spores purple, 8 µ, marked by strong ridges and spines," 8 µ.

Reported from Antigua.

Physarum æneum (List.) R. E. Fries.

• 1898. Physarum murinum var. aeneum Lister, Jour. Bot., XXXVI., p. 117.
• 1903. Physarum aeneum Lister, R. E. Fries, Arkiv. Bot., I., p. 62.

Sporangia sessile, sub-globose or plasmodiocarpous, pinkish-brown or bronze, glossy; peridium double, the outer somewhat cartilaginous, brittle, falling back from the shining, membranous inner wall; capillitium dense, the nodules not large, brown, sometimes aggregated to form a pseudo-columella; spores pale brownish-violet, nearly smooth, 6–8 µ.

Reported from West Indies, Bolivia.[Pg 102]

Related Genus

Trichamphora Junghuhn, p. 12.

• 1838. Trichamphora, Junghuhn, Fl. Crypt. Javanica.

Sporangia discoidal, above concave, saucer-shaped, stipitate; the capillitium variable, anon physaroid, badhamioid, or even as in Didymium.

This genus is set up for the accommodation thus far of the single species following. It differs from Physarella in the apparently constant discoidal shape, absence of trabecules, etc.

Trichamphora pezizoidea Jungh., op. cit.

• 1838. Trichamphora pezizoidea Jungh., op. cit.
• 1854. Didymium zeylanicum Berk. & Br., Hook. Jour. Bot., VI., p. 230.
• 1869. Physarum macrocarpum Fuckel, Symb. Myc., p. 343.
• 1875. Chondrioderma pezizoidea Rost., Mon., p. 424, tab. VIII., Fig. 122.
• 1876. Badhamia fuckeliana Rost., Mon., App., p. 2.
• 1894. Trichamphora pezizoidea Jungh., List., Mycetozoa, p. 89.
• 1911. Trichamphora pezizoidea Jungh., List., Mycetozoa, 2nd ed., p. 90.

Sporangia discoidal or saucer-shaped, gregarious, stipitate, erect or nodding, grayish-white, the peridium thin, breaking irregularly and persistent; stipe subulate, striate, reddish brown, transparent; capillitium variable as above stated; spores pale violet-brown, spinulose or nearly smooth, about 9 µ.

In Mycetozoa, 2nd ed., the spores are described as "dark or pale purplish brown, spinose, spinulose or nearly smooth, 9–17 µ in diameter." This would seem too great a variation even in this protean species. The only specimens in our herbarium are from the Congo valley. The spores are pale and nearly smooth, as in Tilmadoche alba, and 9 µ. Spores 17 µ suggest immaturity; penultimate cell-division.

The synonymy above cited shows how this species has impressed careful students. Doubtless in every case the reference is correct, judging from the specimen each author had before him, although it is hard to see how Chondrioderma might have been suggested.

The species is evidently tropical, though reported from Europe.[Pg 103]

4. Craterium Trentepohl

• 1797. Craterium Trentepohl, Roth, Catal., I., p. 224.

Sporangia more or less distinctly cyathiform, stipitate, the peridium generally plainly of two layers or even of three, opening at the top by circumscission more or less definite, or by a distinct lid, the upper part calcareous often to a marked degree, the lower, cartilaginous, long persistent as a vasiform cup containing the capillitium and spores, the calcareous nodes aggregating more or less to form a pseudo-columella.

This genus is distinguished from Physarum and Badhamia chiefly by the form of the sporangia and the method of dehiscence. The capillitium is in some specimens particularly, of the Physarum type; in others, like that of Badhamia. There are accordingly species that receive at the hands of different authors diverse generic reference as one feature or another in the structure is emphasized in the different cases. It is granted that it is hard to draw the line sometimes between forms in which the dehiscence is irregularly circumscissile and those in which the wall breaks without any regularity whatever, since, in all, the breaking up of the peridium usually begins at the top. Species here included will, however, offer little ambiguity.

Key to the Species of Craterium

1. Craterium paraguayense (Speg.) List.

• 1883. Didymium paraguayense Speg., Fung. Guar. Pug., 1, p. 141.
• 1893. Craterium rubescens Rex, Proc. Philad. Acad. Nat. Sci., p. 370.
• 1894. Craterium rubescens Rex, List., Mycetozoa, p. 71.
• 1899. Craterium rubescens Rex, Macbr., N. A. S., p. 75.
• 1904. Iocraterium paraguayense (Speg.) Jahn, Hedwigia, XLII., p. 302.
• 1911. Craterium paraguayense List., Mycetozoa, 2nd ed., p. 95.

[Pg 104]

Sporangia gregarious, cylindrical or elongate cyathiform, stipitate, dark violet-red, the apex slightly roughened by pale calcareous granules, the peridium longitudinally wrinkled below; dehiscence, irregularly circumscissile; stipe darker, one-half the height of the sporangium, longitudinally wrinkled; capillitium dense, abundantly calcareous; spores violet-brown, minutely roughened, 7–8 µ.

In form resembling the following species, but instantly distinguished by the color, which is red throughout, tinged with purple or violet. The capillitium is badhamioid, as noted by Dr. Rex. Very distinct from P. newtoni in color, form, habit, epispore, etc.

2. Craterium aureum (Schum.) Rost.

• 1803. Trichia aurea Schum., Enum. Pl. Saell., II., p. 207.
• 1829. Craterium mutabile Fries, Syst. Myc., III., p. 154.
• 1875. Craterium aureum (Schum.) Rost., Mon., p. 125.

Sporangia gregarious, globose or obovoid, stipitate, yellow, erect, the peridial wall thin, especially at the summit, where at maturity it breaks up somewhat reticulately, leaving the persistent lower portion with an uneven margin above which projects the pale yellow capillitium; stipe short, orange, or brownish-red, arising from a small hypothallus; capillitium dense, yellow, the nodules not large, irregular, tending to form a pseudo-columella in the centre of the cup; spores minutely warted, violaceous-brown, 8–10 µ.

Fries regards this, which he names C. mutabile, the most distinctly marked species of the genus; chiefly, as it appears, on account of the bright yellow color. This, however, varies. Some specimens before us are gray, showing only a trace of yellow below. In some European specimens a reddish tinge prevails. The form of the sporangium also varies. In typical specimens, unopened, the shape is almost pyriform; opened, we have a cylindric, oftenest lemon-yellow vase, mounted on a short striate stalk. But again, from the same plasmodium, we may have globose sporangia, opening so as to leave only a shallow, salver-shaped base. In this case the stipe is also longer. The plasmodium is said to be "clear lemon yellow."—Massee.

There seems little doubt that Schumacher had in mind the present[Pg 105] species in his Trichia aurea. Rostafinski shows that Fries's synonym, C. mutabile, is founded on a mistake. The earlier specific name is therefore on Rostafinski's authority adopted.

Not common. Pennsylvania, New Jersey, North Carolina, Ohio, Iowa.

3. Craterium leucocephalum (Pers.) Ditmar.

Plate VIII., Fig. 5.

• 1791. Stemonitis leucocephala Gmelin, Syst. Nat., II., p. 1467.
• 1801. Arcyria (?) leucocephala Persoon, Syn. Fung., p. 183.
• 1801. Craterium (?) leucocephalum, Persoon, Syn. Fung., p. 184.
• 1813. Craterium leucocephalum (Pers.) Ditmar, Sturm, Deutsch. Flora, Pilze, p. 21, Pl. 11.
• 1889. Physarum scyphoides Cke. & Balf., Jour. Myc., V., p. 186.
• 1896. Craterium convivale (Batsch) Morg., Jour. Cin. Soc., p. 86.

Sporangia gregarious, short-cylindric or ovate, pure white above, brown or reddish-brown below, stipitate, dehiscence irregularly circumscissile, the persistent portion of the peridium beaker-shaped; stipe short, stout, expanded above into the base of the peridium with which it is concolorous; hypothallus scant; capillitium white or sometimes, toward the centre, brownish, the calcareous nodules large, conspicuous, and persistent; spore-mass black, spores violaceous-brown, minutely spinulose, 8–9 µ.

Distinguished by its white cap from all except the next, from which the markedly different form serves as the diagnostic feature. In some gatherings, curious patches of yellow mark the otherwise snow white cap and sides; these are mere stains, or sometimes definite, crystalline, flake-like bodies, standing out in plain relief on the sporangial wall, or lurking in the larger nodules which are massed along the axis of the cup to form the pseudo-columella here strongly developed. Mr. Lister calls attention to these yellow flakes, and regards them as diagnostic. European specimens show the capillitium yellow, sometimes throughout!

The nomenclature question is here somewhat difficult. Fries heads his list of synonyms with Peziza convivalis Batsch. Batsch simply described Micheli's figure! Now there is nothing in Micheli's figure (Pl. 86, Fig. 14) to enable one to say with certainty which craterium Micheli had in mind, if craterium at all. Nor does Batsch help the[Pg 106] matter when he offers the description following: "Stipitata; acute conica, patens; stipite subdistincto, lineari, brevi, valido. Albicans. In foliis hederae putridis." (Elenchus Fungorum, Batsch, 1783, p. 121.) There is nothing definitive here but the one word "albicans" quoted from Micheli. But this term is applicable the rather to C. minutum, the cups of which whiten with weathering. It may be, as insisted by Fries (Syst. Myc., III., p. 149), that Micheli drew crateriums; but if so, we cannot determine which species.

The specific name here adopted was applied by Persoon probably to this form; but Persoon likewise failed to distinguish the present species from C. minutum (see Syn. Fung., pp. 183, 184), and Fries, op. cit., p. 153. Ditmar, l. c., leaves no doubt as to what he figures and describes, and accordingly the name he first correctly uses is here adopted.

Not common. New England, Pennsylvania, Ohio, North Carolina, Iowa, Colorado, Washington, California; reported from Europe.

4. Craterium cylindricum Massee.

Plate XVI., Fig. 2.

• 1873. Craterium minimum Berk. & C., Grev., II., p. 67.
• 1892. Craterium cylindricum Massee, Mon., p. 268.
• 1894. Craterium leucocephalum Ditm., List., Myc., p. 72, in part.
• 1899. Craterium minimum Berk. & C., Macbr., N. A. S., p. 77.
• 1911. Craterium leucocephalum var. cylindricum List., Mycetozoa, 2nd ed., p. 97.

Sporangia closely gregarious, very small, .5 µ or less, slender, cylindric, almost entirely white, stipitate, the peridium delicate, transparent although calcareous nearly to the base, opening by a dehiscence regularly circumscissile; stipe short, about one-third the total height, clear orange-brown, somewhat furrowed, rising from an indistinct hypothallus; capillitium very lax, physaroid, the calcareous nodules large, rounded, pure white, aggregated at the centre of the cup; spore-mass black, spores minutely roughened, violaceous-brown, 8–9 µ.

This is the common form in the United States. Massee describes it as C. cylindricum Mass., and it seems not to occur in Europe.[Pg 107] Lister has put it in with C. leucocephalum, from which its more delicate structure and elegant cylindrical shape certainly distinguish it. The dehiscence is even more regular than in the preceding species and approaches that of C. minutum Leers., with bleached forms of which it must not be confused. N. A. F., 1400.

C. minimum Berk. & C. has here priority. Massee regards this name as indicating a distinct species. We have been unable to determine what the authors really had before them, and adopt accordingly the first available combination.

New England to Iowa and south; reported also from the orient.

5. Craterium concinnum Rex.

• 1893. Craterium concinnum Rex, Proc. Phila. Acad., p. 370.

Sporangia scattered, usually minute, broadly funnel-shaped, stipitate. The peridium simple, variously colored by innate lime granules, opening by a regular cap or operculum, brownish white, darkest in the centre, always more or less convex; stipe equalling the cup in height, dark brown, longitudinally ridged; the capillitium a close-meshed network, with small rounded or slightly angular masses of ochre-brown lime-granules, larger toward the centre; spores pale brown, minutely warted, 9–10 µ.

This species differs from the following, to which it seems most nearly allied, in form, color, as in the capillitium, and color of the spores. In habitat, however, it seems no less distinct, being found always (?) on the spines of decaying chestnut-burs lying on the ground, and in company with that other peculiar species Lachnobolus globosus.

The range is probably that of the chestnut, Castanea dentata Borkhausen, east of the Mississippi River.

6. Craterium minutum (Leers) Fr.

Plate XV., Fig. 5.

• 1775. Peziza minuta Leers, Fl. Herborn, p. 277.
• 1797. Craterium pedunculatum Trent., Roth., Catal. Bot., I., p. 224.
• 1813. Craterium vulgare Ditmar, Sturm, Deutsch. Fl. Pilze, p. 17.
• 1829. Craterium pedunculatum Trent., Fr., Syst. Myc., III., p. 150.
• 1829. Craterium minutum Leers, Fr., Syst. Myc., III., p. 151.[Pg 108]
• 1893. Craterium pedunculatum Trent., Macbr., Bull. Lab. Nat. Hist. Iowa, II, p. 385.
• 1894. Craterium pedunculatum Trent., Lister, Mycetozoa, p. 70.
• 1899. Craterium minutum (Leers) Fr., Macbr., N. A. S., p. 78.
• 1911. Craterium minutum Fr., List., Mycetozoa, 2nd ed., p. 94.

Sporangia scattered, gregarious, cyathiform or turbinate, grayish brown, stipitate, the peridial wall rather thick, double, opening by a distinct lid which lies usually below the slightly thickened and everted margin of the cup; stipe paler, translucent, about equalling in height the peridial cup, longitudinally wrinkled, with hypothallus scant or none; capillitium physaroid, the calcareous nodules large, white, and generally aggregated at the centre of the cup; spore-mass black, spores by transmitted light violaceous, minutely warted, 8–10 µ.

This is the most highly differentiated of the whole series. The cup is shapely and well defined, while the lid is not only distinct, but is a thin, delicate membrane of slightly different structure when compared with the peridial wall. It is in all the specimens before us much depressed below the mouth of the sporangium, and the whole structure in our specimens corresponds with Fries' description of C. pedunculatum Trent., while specimens received from Europe correspond to Fries' account of C. minutum Leers. Nevertheless we are assured that the two forms are in Europe developed from the same plasmodium, and therefore adopt the earlier specific name as above. N. A. F., 2500. This is probably Fungoides convivalis of Batsch and Micheli.

In this species yellow sporangia are sometimes seen. Miss Currie reports from Toronto such variation and in Europe the case seems not unusual.

In fact, there is a yellow tinge about the sporangia of every species listed here, except the first. With the same exception, the plasmodium in every case is yellow.

Common throughout the eastern United States, west to Iowa, Colorado, and south to Louisiana; cosmopolitan.

5. Physarella Peck.

• 1882. Physarella Peck, Bull. Torr. Bot. Club, IX., p. 61.

Sporangium pervious to the base, the interior walls forming a persistent spurious columella; capillitium composed of filaments with[Pg 109] here and there minute knot-like thickenings, straight tubes containing lime-granules extending from the exterior to the interior walls of the sporangium, persistently attached to the former.[31]

Such is Dr. Peck's original description of this most peculiar genus. The form of the sporangium in the only species is very variable, but in typical cases is vasiform, the peridial wall at the apex introverted. The capillitium is like that of Tilmadoche, except for the presence of the "straight tubes" emphasized in the original description. These are very remarkable and at once diagnostic. They take origin in the sporangial wall and pass across to the "columella"; but at the dehiscence of the sporangium, in typical cases, they remain attached at the points of origin, projecting as stout spine-like processes.

Physarella oblonga (Berk. & C.) Morg.

Plate VIII., Figs. 4, 4 a, 4 b, 4 c; Plate XVI., Figs. 1, 1 a, 1 b, and 6.

• 1873. Trichamphora oblonga Berk. & C., Grev., II., p. 66.
• 1876. Tilmadoche oblonga (Berk. & C.) Rost., Mon. App., p. 13.
• 1876. Tilmadoche hians Rost., Mon. App., p 14.
• 1882. Physarella mirabilis Peck, Bull. Torr. Bot. Club, IX., p. 61.
• 1893. Physarella oblonga (Berk. & C.) Morg., Jour. Cin. Soc., p. 79.
• 1894. Physarella mirabilis Peck, List., Mycet., p. 68.
• 1899. Physarella oblonga (Berk. & C.) Morg., Macbr., N. A. S., p. 71.
• 1911. Physarella oblonga Morg., List., Mycet., 2nd ed., p. 91.

Sporangia scattered or gregarious, typically cup-shaped or sub-infundibuliform, stipitate, erect or cernuous, but varying through low salver-shaped cups, to irregular applanate and sessile masses, the peridium thin but firm, tawny, roughened by numerous yellowish calcareous scales, at length ruptured above and often reflexed in the form of petal-like segments from which project upwards the spiniform trabecules of the capillitium; stipe when present long, terete, red, arising from a scant hypothallus and extended within the sporangium to meet the tubular "columella"; capillitium of delicate violaceous threads seldom branched or united, radiating from the columella with few calcareous nodular expansions, but supported by stout yellow calcareous trabecules, running parallel to the capillitial threads, long adherent to the sporangial wall; spores smooth, globose violet-brown, 7–8 µ.

[Pg 110]Not uncommon in wet places. New York, Ohio, Iowa, South Dakota, Louisiana, Nicaragua; reported also from Ceylon, Java, etc.

Not the least remarkable feature of this remarkable species is the variation in the form of the fruit or sporangia. We have specimens from Louisiana (Rev. Langlois) which show no trace of columella, the whole structure involute and plicate, short stipitate, recalling the extremest complexity of such a species as P. polycephalum. Vid. Pl. XVI., Fig. 6. Moreover, in these specimens the calcareous deposits are white and not yellow, giving the entire fructification a grayish aspect. Yet there is no doubt we have here simply an exaggerated abnormality of the species; the spores are identical in size, color, and surface. Plasmodium bright yellow. Dr. Peck gave to his forms the name Physarella mirabilis; but specimens sent by Michener of Pennsylvania, and by Berkeley and Curtis described as Trichamphora oblonga (Grev., II., p. 66), are the same thing. N. A. F., 1212.

Physarella lusitanica Torrend is a globose form depressed above or betimes discoidal, occurring on Eucalyptus trees in Portugal. P. oblonga is so variable in form that it sometimes suggests a different genus. Forms of it have been mistaken for Fuligo gyrosa R., etc. Professor Torrend would include here Physarum javanicum (Rac.), i. e. Tilmadoche javanica as Raciborski saw it! We may not too often reflect that genera are purely artificial things set up for our convenience; but surely Physarella as a natural genus is distinct enough to all.

6. Cienkowskia Rost.

• 1873. Cienkowskia Rost., Versuch, p. 9.

Fructification plasmodiocarpous, irregularly dehiscent, the wall a thin cartilaginous membrane destitute of lime, except the capillitial attachments within; capillitium scanty but rigid, and characterized everywhere by peculiar hook-like branchlets, free and sharp-pointed, the spores as in Physarum, etc.

The genus contains, so far, but a single species:[Pg 111]—

Cienkowskia reticulata (Alb. & Schw.) Rost.

Plate XIV., Figs. 2, 2 a, 2 b.

• 1805. Physarum reticulatum Alb. & Schw., Cons. Fung., p. 90.
• 1829. Diderma reticulatum Fr., Syst. Myc., III., p. 112.
• 1873. Cienkowskia reticulata (Alb. & Schw.) Rost., Versuch, p. 9.

Plasmodiocarp an elongated, irregularly limited, close-meshed net, closely applied to the substratum, the wall thin, transversely rugulose, and roughened, dull orange-yellow, splashed here and there with scarlet, anon entirely red, within marked by transverse calcareous ridges, supporting in part the calcareous system of the capillitium; capillitium of delicate, rigid, reticulating yellow tubules or threads with numerous free, uncinate or sickle-shaped branchlets, and large, irregular, calcareous plates, more or less transverse to the axis of the sporangium, attached to the peridial walls, as if to form septa, ordinary calcareous nodules few; spore-mass jet-black, spores, by transmitted light, violaceous, minutely roughened, 9–10 µ.

A very rare species, as it appears, easily recognized by the Coddington even, much more by the microscopic characters quoted; probably often overlooked by the collector, as to the naked eye it presents the appearance of some imperfectly developed, dried-up plasmodium. Very unlike Physarum serpula Morgan, not infrequently offered by collectors as Cienkowskia. It is Diderma reticulatum of Fries, who, strangely enough, thought it might be a plasmodial phase of Diderma (i. e. Leocarpus) fragile (Syst. Myc., III., p. 102).

Eastern United States, Europe, Java, Ceylon, California. See under L. fragilis, next following.

7. Leocarpus (Link) Rost.

• 1809. Leocarpus Link, Diss., I., p. 25.

Sporangia sessile, or short stipitate; peridial wall double, the outer thick, destitute of lime, polished, shining within and without, the inner very delicate, enclosing the capillitium and spores; capillitium of two, more or less, distinct systems, the one a delicate network of hyaline, limeless threads, the other calcareous throughout, or nearly so, the meshes large and the threads or tubules broad; columella none, although a pseudo-columella may sometimes be detected.[Pg 112]

This genus was by Link established on characters purely external. Rostafinski supplemented Link's definition by calling attention to the peculiar character of the capillitium and to microscopic characters in general. The outer peridium is thick and strong, unlike the ordinary structure in Physarum. Some physarums, however, have a very similar outer wall; P. brunneolum, for instance; compare the peridium of P. citrinellum. In dehiscence and structure there is also some resemblance to some species of Diderma, and by Persoon and Fries the common species was so referred, but the capillitium is again definitive.

A critical study of all these things really begins with Rostafinski's microscope. Under his definition of the present genus P. squamulosum Wingate and P. albescens Ell. might well be entered here. Such course at present would but increase confusion, and until by future research the ontogeny of all these, and so their relationship, shall be more exactly known, the genus may be left with its historic species,—montotypic.

Leocarpus fragilis (Dickson) Rost.

Plate VIII., Figs. 3, 3 a, 3 b.

• 1785. Lycoperdon fragile Dickson, Fasc. Pl. Crypt. Brit., I., p. 25.
• 1795. Diderma vernicosum Persoon, Ust. Ann. Bot., XV., p. 34.
• 1809. Leocarpus vernicosum Link, Diss., I., p. 25.
• 1875. Leocarpus fragilis (Dicks.) Rost., Mon., p. 132.

Sporangia gregarious or clustered, sessile or stipitate, obovoid, rusty or spadiceous-yellow, shining; peridium opening at maturity in somewhat stellate fashion; stipe filiform, white or yellow, weak and short; spores dull black, spinulose, 12–14 µ.

A common species, distributed through all the world, Iowa to Tasmania. Recognizable at sight by the form and color of the sporangia. In shape and posture these resemble the eggs of certain insects, and, occurring upon dead leaves, generally where these have drifted against a rotten log, they might perchance be mistaken for such structures. With no other slime-moulds are they likely to be confused. The outer peridium opens irregularly, or more rarely[Pg 113] stellately. At centre of the capillitium is a calcareous core. The plasmodium is yellowish white, spread in rich and beautiful reticulations. N. A. F., 1123.

A plasmodiform gathering of this species which will be mistaken for an entirely different thing, is yellow, sessile, and has adherent spores; looks like a badhamia, but is after all a leocarpus and probably belongs here. The spores are irregularly clustered and the badhamioid section of the capillitium seems now dominant.

California.

B. DIDYMIACEÆ

Key to the Genera of the Didymiaceæ

1. Mucilago (Mich.) Adans.

• 1729. Mucilago Micheli, Nov. Pl. Gen., in part.
• 1763. Mucilago (Mich.) Adanson, Fam. des Pl., II., p. 7.
• 1791. Spumaria Pers. in Gmelin, Syst. Nat., II., p. 1466.

Fructification æthalioid, consisting generally of large cushion-shaped masses covered without by a white foam-like crust; within, composed of numerous tubular sporangia, developed from a common hypothallus, irregularly branched, contorted and more or less confluent; the peridial wall thin, delicate, frosted with stellate lime-crystals, which mark in section the boundaries of the several sporangia; capillitium of delicate threads, generally only slightly branched, terminating in the sporangial wall, marked with occasional swellings or thickenings.

By the descriptions offered by most authors, and especially by Rostafinski's figures (Mon., Pl. ix.), a pronounced columella is called for in the structure of Spumaria. The individual sporangia rise from a common hypothallus, and occasionally portions of this run up and[Pg 114] give to a sporangium the appearance of being stipitate. Sometimes also this upper extension of the hypothalline protoplasm passes beyond or behind the base of the sporangium or between two or more, and is more or less embraced by these in their confluent flexures. This, it seems, suggested Rostafinski's elaborate diagram, Fig. 158; at least, none other form of columella is shown by American materials at hand.

1. Mucilago spongiosa (Leyss.) Morgan.

Plate VII., Fig. 6, 6 a, 6 b.

• 1783. Mucor spongiosus Leysser, Fl. Hal., p. 305.
• 1791. Reticularia alba Bull., C. Fl. France, p. 92.
• 1791. Spumaria mucilago Pers., Gmel., Syst. Nat., II., 1466.
• 1805. Spumaria alba (Bull.) DC., Fl. Fr., II., p. 261.
• 1897. Mucilago spongiosa (Leyss.) Morg., Bot. Gaz., XXIV., p. 56.

Æthalium white or cream-colored, of variable size and shape, half-an-inch to three inches in length and half as thick, the component sporangia resting upon a common hypothallus and protected by a more or less deciduous calcareous porous cortex; peridial walls thin, and where exposed iridescent, generally whitened by a thin coating of lime crystals; capillitium scanty, of simple, mostly dark-colored, slightly anastomosing threads; columella indefinite or none; hypothallus white, spongy; spore-mass black, spores violaceous, exceedingly rough, large, 12–15 µ.

Very common in all the eastern United States and the Mississippi valley, south to Texas. The plasmodium is dull white, of the consistence of cream, and is often met with in quantity on beds of decaying leaves in the woods. In fruiting the plasmodium ascends preferably living stems of small bushes, herbaceous plants, or grasses, and forms the æthalium around the stem some distance above the ground. The cortex varies in amount, is also deciduous, so that weathered or imperfectly developed forms probably represent the var. S. cornuta Schum.

Two varieties of this species are recognized; the one from Bolivia, var. dictyospora described by Mr. R. E. Fries (Arkiv. for Botanik Bd. 1, p. 66) differs from the type chiefly in its finer capillitial threads its darker spores with longer spines and fine reticulate sculpture; the other from Colorado, var. solida described by Professor[Pg 115] Sturgis differs, as the name implies, principally in its greater compactness and slightly smaller calcareous crystals; a desert phase.

2. Didymium (Schrad.) Fr.

• 1797. Didymium Schrad., Nov. Gen. Plant., p. 20, in part.
• 1829. Didymium (Schrad.) Fr., Syst. Myc., III., p. 113.
• 1875. Didymium (Schrad.) DeBy., Rost., Versuch, p. 13.

Sporangia distinct, stipitate, sessile or even plasmodiocarpous, never æthalioid; the peridium thin, irregular in dehiscence, covered with a more or less dense coating of calcareous crystals; columella more frequently present; capillitium of delicate threads, simple or sparingly branched, extending from the columella to the peridial wall.

The genus Didymium, as set up by Schrader l. c., included a number of species now assigned to Diderma, Lepidoderma or Lamproderma. Fries set out the didermas; DeBary and Rostafinski completed the revision by setting out the remaining alien forms.

The genus is among Myxomycetes instantly recognized by the peculiar form of its calcareous deposits, stellate crystals coating, or merely frosting, usually distinct sporangia.

Key to the Species of Didymium

1. Didymium complanatum (Batsch) Rost.

Plate XVI., Fig. 8.

• 1786. Lycoperdon complanatum Batsch, Elench. Fung., I., p. 251.
• 1829. Didymium serpula Fr., Syst. Myc., III., p. 126, Rost., App., p. 21.
• 1875. Didymium complanatum (Batsch), Rost., Mon., p. 151.
• 1899. Didymium complanatum (Batsch) R., Macbr., N. A. S., p. 85.
• 1911. Didymium complanatum Rost., List., Mycetozoa, 2nd ed., p. 127.

Fructification plasmodiocarpous, creeping, flattened, vein-like, annulate or reticulate, the dark-colored peridium covered with white, but not numerous crystals; hypothallus none; columella none; capillitium much branched, violaceous threads combined to form a rather dense net which bears numerous, peculiar, rounded vesicles, yellowish in color, 30–50 µ in diameter; spores minutely warted, 7–9 µ, violaceous-brown.

The defining characteristics here are the curious supplementary vesicles. These are evidently plasmodic, embraced, shot-through, by all the neighboring capillitial threads, withal warted like a spore. They remind of the curious, belated, spore-like but giant cells found in stipes, as in arcyriaceous forms. With all the wealth of his prolix,[Pg 117] poetic, metaphoric tongue, the Polish author gives them abundant consideration. In the Mon., Tab. IX., Figs. 166 and 180, he clearly shows the structure, although in the explanation of the plate he has strangely mixed this species with D. crustaceum Fr. Under D. serpula Fries may refer to the present species, although there is nothing in his description to determine the fact. The same thing may be said of the description and figures of Batsch. Rostafinski, in the Monograph, seems to have been satisfied as to the identity of Batsch's materials: in the Appendix, he writes D. serpula, but gives no reason.

Rare. New York. England, France, Germany.

2. Didymium anellus Morgan.

Plate XVIII., Fig. 7.

• 1894. Didymium anellus Morgan, Jour. Cin. Soc., p. 64.
• 1899. Didymium anellus Morg., Macbr., N. A. S., p. 85.
• 1911. Didymium anellus Morg., Lister, Mycetozoa, 2nd ed., p. 134.

Plasmodiocarp in small rings or links, then confluent and elongated, irregularly connected together, bent and flexuous, resting on a thin venulose hypothallus, or sometimes globose, the peridium dark colored, with a thin layer of stellate crystals, irregularly ruptured; capillitium of slender, dark-colored threads, which extend from base to wall, more or less branched, and combined into a loose net; columella a thin layer of brown scales; spores globose, very minutely warted, violaceous, 8–9 µ.

This minute species resembles a poorly developed, or sessile, phase of D. melanospermum. Some of the sporangia (?) are spherical; such show a very short dark stalk. The columella is scant, and the spores are smaller than those of D. melanospermum.

Ohio. Reported more recently from Europe and Ceylon.

3. Didymium wilczekii Meylan.

• 1908. Didymium wilczekii Meyl., Bull. Soc. Vaud. Sci. Nat., XLIV., p. 290.
• 1911. Didymium wilczekii Meyl., List., Mycetozoa, 2nd ed., p. 134.

Plasmodiocarpous, dehiscing irregularly, columella scant; capillitium abundant, the threads brown, anastomosing, forming an elastic net; spores purple-brown, minutely spinulose, 10–12 µ.[Pg 118]

Resembling plasmodiocarpous forms of D. squamulosum, a montane var.; small and delicate, our specimen about 16 × 6 mm. Evidently not common; collected but once by Professor Bethel at an altitude of 11,000 feet, Rocky Mountains of Colorado.

Reported in Switzerland and Sweden.

In certain Swiss gatherings made in 1913 Miss Lister finds capillitial threads with spiral tæniæ as in Trichia! (Jour. of Bot., Apr. 1914.) The threads in our specimen are roughened, somewhat as in D. squamulosum, though less strongly; the spores are nearly smooth, fuliginous at first, paler and violaceous when saturate.

4. Didymium fulvum Sturgis.

• 1917. Didymium fulvum Sturgis, Mycologia, IX., p. 37.

Sporangia gregarious, sessile, elongate or forming curved plasmodiocarps, sometimes confluent, rarely sub-globose, concave beneath, pale-raw-umber in color, 0.5–0.8 mm. in diameter, occasionally seated on a concolorous, membranous, lime-encrusted hypothallus which may form pseudo-stalks; sporangium wall membranous, stained with yellow blotches, thickly sprinkled with clusters of large acicular crystals of pale-yellowish lime; columella very much flattened or obsolete; capillitium an abundant network of delicate, almost straight or flexuose, pale-purple or nearly hyaline threads, frequently with dark, calyciform thickenings as in Mucilago, and occasionally showing fusiform, crystalline blisters; spores dark-purplish-brown, coarsely tuberculate, the tubercles usually arranged in curved lines, paler and smoother on one side, 12.5 to 14.5 µ. Colorado.

5. Didymium crustaceum Fr.

• 1829. Didymium crustaceum Fr., Syst. Myc., III., p. 124.

Sporangia closely aggregated, globose, or by compression deformed, sessile, snow-white, by virtue of the remarkably developed covering of calcareous crystals by which each sporangium is surrounded as if to form a crust, the peridium membranous, colorless, usually shrunken above and depressed; columella pale, small, or obsolete; hypothallus scant or vanishing; capillitium of rather stout violaceous threads seldom branched except at the tips, where they are pale and often[Pg 119] bifid, or more than once dichotomously divided; spores strongly warted, globose, violet-brown, 10–13 µ.

This species has in some ways all the outward seeming of a diderma, but cannot be referred to that genus because of the crystalline character of its crust. This is a very marked structure; loosely built up of very large crystals, it is necessarily extremely frail, nevertheless persists, arching over at a considerable distance above the peridium proper. Sometimes, however, caducous, evanescent.

The sporangia are said to be sometimes stipitate. This feature does not appear in any of the material before us. Lister in Mycetozoa Pl. XL., c. draws the capillitium much more delicate than it appears in our specimens. The hypothallus is sometimes noticeable under some of the sporangia where closely crowded, but is not a constant feature.

Rostafinski (by typographical error?) confused in the Monograph, pp. 164, 165, this species with Persoon's Physarum confluens. In the Appendix he substitutes the Friesian nomenclature. Persoon's description of his species is insufficient, and throws no light on the problem whatever.

Rare. Iowa; Black Hills, South Dakota. Reported common in Europe. Canada; Vancouver Island to the St. Lawrence.

6. Didymium squamulosum (Alb. & Schw.) Fries.

• 1805. Diderma squamulosum Alb. & Schw., Consp. Fung., p. 88.
• 1816. Didymium effusum Link, Diss., II., p. 42.
• 1829. Didymium squamulosum (Alb. & Schw.), Fries, Syst. Myc., III., p. 118.
• 1875. Didymium effusum (Link) Rost., Mon., p. 163.
• 1894. Didymium effusum (Link) List., Mycetozoa, p. 99.

Sporangia, in typical forms, gregarious, globose or depressed-globose, gray or snow-white, stipitate; the peridium a thin iridescent membrane covered more or less richly with minute crystals of lime; the stipe when present, snow-white, fluted or channelled, stout, even; columella white, conspicuous; hypothallus usually small or obsolete; capillitium of delicate branching threads, usually colorless or pallid, sometimes with conspicuous calyciform thickenings; spores violaceous, minutely warted or spinulose, 8–10 µ.[Pg 120]

This, one of the most beautiful species in the whole series, is remarkable for the variations which it presents in the fruiting phase. These range all the way from the simplest and plainest kind of a plasmodiocarp with only the most delicate frosting of calcareous crystals up through more or less confluent sessile sporangia to well-defined elegantly stipitate, globose fruits, where the lime is sometimes so abundant as to form deciduous flaky scales. The hypothallus, sometimes entirely wanting, is anon well developed, even continuous, venulose, from stipe to stipe. The capillitium varies much in abundance as in color; when scanty, it is colorless and in every way more delicate, when abundant, darker in color and sometimes with stronger thickenings.

D. fuckelianum Rost., as shown in N. A. F., 2090, and in some private collections, seems to be a rather stout phase of the present species; the stipe is more abundantly and deeply plicate, is sometimes tinged with brown, and the capillitium is darker colored and coarser than in what is here regarded as the type of the species; but withal the specimens certainly fail to meet the requirements of Rostafinski's elaborate description and figure, Mon., p. 161 and Fig. 154.

D. effusum Link, probably stands for a sessile form of this species, but Link's brief description (1816) is antedated by the much better one of Albertini and Schweinitz, l. c.

Generally distributed throughout the wooded regions of North America, from New England to Nicaragua, and from Canada to California. Not uncommon about stable-manure heaps, in flower beds, and on richly manured lands. July, August.

Nicaragua specimens not only show a continuous vein-like hypothallus, but have the peridia often confluent, the columellæ in such cases confluent, the stipes distinct. Furthermore, the largest spores reach the limit of 12.5 µ, and perhaps the larger number range from 10–12.5 µ, and all are very rough. This corresponds with D. macrospermum Rost., which is distinguished, says the author (Mon., p. 162, opis), "chiefly by the large and strongly spinulose spores." However, the same sporangium in our Central American specimens yield spores 9.5–12.5 µ, a remarkable range. So that D. macrospermum on this side the ocean, at least, cannot be distinguished from[Pg 121] D. squamulosum, as far as spores are concerned. A similar remark may be made relative to the form of the columella which Rostafinski, in his figures especially, would make diagnostic. The columella in the sporangia with largest and roughest spores is that of a perfectly normal D. squamulosum.

7. Didymium melanospermum (Pers.) Macbr.

Plate VII., Figs. 3, 3 a.

• 1794. Physarum melanospermum Pers., Röm. N. Mag. Bot., p. 89.
• 1797. Didymium farinaceum Schrader, Nov. Gen. Pl., p. 26, t. 5, Fig. 6.

Sporangia gregarious, hemispheric, depressed, umbilicate below, stipitate or sessile; the peridium firm, dull brown in color, frosted with minute crystals of lime, breaking irregularly; stipe, when present, short, stout, dull black, opaque, arising from a broad base or hypothallus; columella large, prominent; dark-colored, rough above, concave below; capillitium of more or less sinuous, usually dark-colored threads, sparingly branched, and often with calyciform thickenings; spore-mass black, spores by transmitted light pale, purplish-gray, spinulose or rough, 10–12 µ.

A well-marked and common species, distinguished by its depressed sporangium and dark-colored, opaque stipe. The latter is usually very short, almost completely concealed in the concavity of the umbilicate sporangium. The columella is dark-colored, forming the floor of the peridial cavity.

Persoon first named this species as here. Later on, Uster's Ann., XV., 6, he substituted villosum as a more appropriate specific name. Schrader rejects both names given by Persoon as unsuitable, and suggests farinaceum. Schrad., op. cit., p. 27.

New England, Ohio, Missouri, Alabama, Iowa, Nebraska; Europe; probably cosmopolitan.

8. Didymium minus Lister.

Plate X., Figs. 4, 4 a, 4 b.

• 1892. Didymium farinaceum Schr., var. minus, List., Mycetozoa, p. 97.
• 1896. Didymium minus List., Morg., Jour. Cin. Soc., p. 61.
• 1899. Didymium minus List., Macbr., N. A. S., p. 89.

[Pg 122]

Sporangia gregarious, depressed-globose, umbilicate below, whitish or gray, small, about ½ mm., stipitate; stipe erect, rather slender, black, faintly striate, about equal to the sporangium in the horizontal diameter; columella distinct, dark brown, globose or depressed-globose, attaining in some cases the centre, rough; capillitium delicate, almost colorless, radiating, sparsely branched; spores in mass dark brown, by transmitted light violet-tinted, minutely roughened, 8–10 µ.

Probably more common than the preceding, and generally mistaken for it. Distinguished by its smaller size, longer and more slender stem, and general trim, well-differentiated appearance. Certainly very near the preceding, of which Mr. Lister regards it as merely a variety. Professor Morgan thought it in this country the more common form.

New York, Ohio, Iowa; reported from Europe, Africa, South America.

9. Didymium clavus (Alb. & Schw.) Rabenhorst.

• 1805. Physarum clavus Alb. & Schw., Consp. Fung., p. 96.
• 1829. Didymium melanopus Fries, Syst. Myc., III., p. 114.
• 1844. Didymium clavus (Alb. & Schw.) Rabh., Ger. Cr. Fl., No. 2282.
• 1875. Didymium clavus (Alb. & Schw.) Rost., Mon., p. 153.
• 1899. Didymium clavus (Alb. & Schw.) Rabenh., Macbr., N. A. S., p. 90.
• 1911. Didymium clavus Rost., List., Mycet., 2nd ed., p. 128.

Sporangia gregarious, pale gray, discoid or pileate, depressed, stipitate; the peridium dark-colored, frosted with calcareous crystals above, naked below; stipe short, slender, tapering upward, furrowed, arising from a hypothallus more or less distinct, black; columella obsolete; capillitium of delicate threads, pale or colorless, little branched; spores violaceous, pale, nearly smooth, 6–8 µ.

This species is well differentiated, easy of recognition by reason of its peculiar discoid sporangium, calcareous above, naked and black beneath. D. neglectum Massee, reported from Philadelphia, is said to be a slender form of the present species. The figures of D. clavus by Albertini and Schweinitz are excellent, as also the description.

Not common. Pennsylvania, Ohio, Iowa.[Pg 123]

10. Didymium nigripes (Link) Fries.

Plate VII., Figs. 2, 2 a, 2 b.

• 1809. Physarum nigripes Link, Obs. Diss., I., p. 27.
• 1818. Physarum microcarpon Fr., Sym. Gast., p. 23.
• 1829. Didymium nigripes (Link) Fr., Syst. Myc., III., p. 119.
• 1875. Didymium microcarpon (Fr.) Rost., Mon., p. 157.
• 1896. Didymium microcarpon Fr., Morg., Jour. Cin. Soc., p. 61.

Sporangia gregarious, globose or hemispheric, umbilicate beneath, small, white, stipitate; the peridium smoky, covered with minute calcareous crystals; stipe slender, erect, black, opaque; hypothallus scutate, black; columella distinct, globose, black or dark brown; capillitium of delicate threads, pale brown or colorless, with occasional brown thickenings or nodes, sparingly branched; spores pale, violaceous by transmitted light, minutely warted, 6–8 µ.

This is D. microcarpon Rost. Fries, l. c., acknowledges the priority of Link's appellation, and discards microcarpon. Rostafinski adopted microcarpon simply because he thought it more appropriate. Fries describes the columella "none or black." It is doubtful whether we have the typical Friesian form on this continent. The fructification is in our specimens small, about .4 mm., and the spores, as noted by Morgan, small; otherwise the species is hardly more than a variety of the next. Under the name D. nigripes Lister groups our Nos. 10, 11, 12. N. A. F., 1393, represents Dr. Rex's conception of the present species.

Not common. New York, Ohio, Iowa.

11. Didymium xanthopus (Ditmar) Fr.

Plate XVI., Fig. 10.

• 1817. Cionium xanthopus Ditmar, Sturm, Deutsch. Fl., III., p. 37, t. 43.
• 1829. Didymium xanthopus (Dit.) Fr., Syst. Myc., III., p. 120.
• 1873. Didymium proximum Berk. & C., Grev., II., p. 52.
• 1892. Didymium microcarpon (Fr.) Rost., Macbr., Bull. Lab. Nat. Hist. Iowa, II., p. 146, in part.
• 1894. Didymium nigripes Fr., List., Mycetozoa, p. 98, in part.

Sporangia gregarious, white, globose, slightly umbilicate, stipitate; the peridium thin, and nearly or quite colorless, frosted with crystals of lime; the stipe yellowish or yellowish brown, corneous, erect, subulate,[Pg 124] slender; hypothallus none; columella pale or white, turbinate, globose or depressed-globose; capillitium of dull brown, or colorless threads more or less branched, always white at the tips; spores violaceous, nearly smooth, 7.5–8.5 µ.

This seems to be the most common form in the United States. It is distinguished from the preceding by the longer, more delicate, generally orange-yellow, stem with pale or white columella. The spores also average a shade larger. N. A. F., 412 and 2089, are illustrations of D. xanthopus. The columella in blown-out specimens is very striking, well confirming the diagnosis of Fries, "valde prominens, globosa, stipitata, alba." Berkeley makes the color of the capillitium diagnostic of D. proximum, but this feature is insufficient.

Eastern United States; common.

12. Didymium eximium Peck.

Plate XVI., Figs. 11, 11 a, 11 b.

• 1879. Didymium eximium Peck, Rep. N. Y. Mus., XXXI., p. 41.

Sporangia scattered, dull grayish-yellow or gray, depressed-globose, umbilicate, minute, stipitate; the peridium comparatively thick, tenacious, especially persistent below, tawny or yellow; the stipe pale brown or orange, erect, even or slightly enlarged at base; hypothallus scant or none; columella prominent, more or less discoidal, rough, or spinulose, especially on the upper surface, yellow; capillitium not abundant, pale fuliginous, often branching and anastomosing so as to form a loose net; spores nearly smooth, dark violaceous by transmitted light, 8.5–9.5 µ.

The species differs from D. xanthopus in several particulars,—in the much firmer, more persistent, and less calcareous peridium, in the more complex capillitium, in the darker and larger spores, and especially in the peculiar and prominent columella, which is not only rough, but even "sometimes spinulose even to the extent of long spicules penetrating to one-third the height of the sporangia." N. A. F., 2493.

As stated under No. 8, these last two species are called varieties only of D. nigripes. They are so retained in Mycetozoa, 2nd ed.[Pg 125] Since, however, they are the usual presentation of the species in the United States, it seems wise to let them stand for the present, as here. They are quite distinguishable; D. eximium especially well marked.

Apparently rare, it yet ranges from New York to eastern Iowa, in colonies rather large. Okoboji Lake;—fine!

13. Didymium trochus List.

• 1898. Didymium trochus List., Jour. Bot., XXXVI., p. 164.

Sporangia plasmodiocarpous, hemispherical or turbinate, white, sessile or very short-stalked, cream-colored or white; peridium double, the outer shell-like, the inner membranaceous, more or less adherent to the outer, both caducous together, leaving the thickened base surrounding an expanded columella; stipe, when present, very short, stout; capillitium colorless, nearly simple; spores brownish-purple, strongly warted, 9–10 µ.

On decaying leaves, rotten cactus, yucca, etc., Monrovia, California; Bethel.

Reported from England on beds of leaves or straw; in Portugal Dr. Torrend finds it on or in dead leaves of Agave americana! Evidently an American species, and belonging to arid regions; its occurrence in England surprising!

14. Didymium annulatum Macbr. n. s.

Plate XX., Figs. 4, 4 a.

Sporangia small, scattered, annulate, not only without columella but perforate when the stipe is broken, umbilicate above and below, grey, coated with crystalline frustules, opening irregularly about the periphery; stipe white, or pallid, fluted, tapering upward from a distinct hypothallus; capillitium scanty consisting of delicate, sparsely branching threads, the branchlets anastomosing more or less at length, attached to the peridial wall, radiating from the rim of the slightly depressed top of stipe, without special thickenings save at the insertion of the ramules a triangular enlargement is usual and of dark or pallid shade; spores smooth; however they show three or four spots[Pg 126] on the hemisphere and other minute but variable markings; 9–10 µ. Seattle, Washington.

Differs from D. nigripes in color of the stipes, capillitium, spore-diameter, etc.

15. Didymium dubium Rost.

• 1875. Didymium dubium Rost., Mon., p. 152.
• 1892. Didymium listeri Mass., Mon., p. 244.
• 1894. Didymium dubium Rost., List., Mycetozoa, p. 95.
• 1911. Didymium dubium Rost., List., Mycetozoa, 2nd ed., p. 126.

Fructification wholly plasmodiocarpous, snow-white, small, 2–6 mm., flat and thin; the outer wall double, membranous within, calcareous-crystalline without; columella none; capillitium simple of rather thick, vertical, brown threads, sparingly united laterally, and only occasionally furcate at the ends, especially above; spores minutely spinulescent, violaceous pale, 12–15 µ.

Massee thought English specimens out of harmony with the original description and gave them a new name. To refuse this, Lister enlarges the range of spore-measurements and disregards some of Rostafinski's specifications as to capillitium. Our specimens are as described.

Bohemia. England. Shores of Lake Okoboji, Iowa.

This is indeed a doubtful form. It differs from D. difforme chiefly in that the outer calcareous shell is not smooth, but is covered with abundant loose crystals, frosted. The spores are paler but about the same size. The frosting may be incident to local climatic conditions at the time and place of desiccation.

16. Didymium difforme Duby.

• 1797. Diderma difforme Pers. Tentamen Disp. Meth., p. 19.
• 1830. Didymium difforme Duby., Bot. Gall., ii., p. 858.
• 1875. Chondrioderma difforme Pers., Rost., Mon., p. 177.
• 1894. Didymium difforme Duby., List., Mycetozoa, p. 94.
• 1899. Diderma personii Macbr., N. A. S., p. 96.
• 1911. Didymium difforme Duby., List., Mycetozoa, 2nd ed., p. 124.

Plasmodiocarpous, the smooth, white outer peridium separable from the thin, colorless or purplish inner layer; capillitium of rather[Pg 127] coarse, flat, dichotomously branching threads, broader below; spores minutely warted, or almost smooth, dark brown, 12–14 µ.

The white crust-like outer wall has more than once carried this species into Diderma. It is still doubtful whether we are here dealing with Chondrioderma calcareum Rost. Miss Lister cites a variety, S. difforme comatum, with more abundant capillitium which may represent Rostafinski's species.

Evidently rare in the United States; reported more common in Europe and eastward. In our specimens the crust-like outer peridium shows crystals on the broken edge only; the body of the object, as its outer surface seems to be amorphous.

17. Didymium quitense (Pat.) Torr.

• 1895. Chondrioderma quitense Pat., Bull. Soc. Myc. Fr., XI., p. 212.
• 1909. Didymium quitense (Pat.) Torr., Flor. Myxom., p. 150.
• 1911. Didymium quitense Torr., List., Mycetozoa, 2nd ed., p. 126.
• 1913. Didymium quitense (Pat.) Torr., Sturg., Myx., Col. II., p. 446.

Sporangia more or less plasmodiocarpous, scattered, depressed, white; the outer peridium distinct, crust-like, remote from the thin membranous inner wall; columella undefined; capillitium brown, much branched, forming a network especially outwardly; spores very dark violaceous-brown, rough with a tendency to obscure reticulation; 12–14 µ.

This species is different from D. difforme chiefly in the rougher and somewhat banded epispore. It is reported from Ecuador by Father Torrend, and from Colorado mountains by Dr. Sturgis to whose kindness I am indebted for the specimens here described. Evidently a high mountain species.

Colorado.

18a. Didymium anomalum Sturg.

Plate XIX., Figs. 13 and 13 a.

• 1913. Didymium anomalum Sturg. Myxomycetes of Col., II., p. 444

Sporangia in the form of very thin effused grey plasmodiocarps, 2–10 cm. long, 1 mm. or less in thickness. Wall single or membranous, hyaline or yellowish, with rather scanty deposits of small, stellately[Pg 128] crystalline or amorphous lime. Columella none. Capillitium consisting entirely of straight membranous, tubular, columns, extending from the base to the upper wall of the plasmodiocarp, 7–22 µ thick and usually containing small crystalline masses of lime. Spores bright violet-brown, minutely and irregularly spinulose, 10–11.5 µ diam.

Hab. on the inner bark of Populus. Colorado Springs, Colo., July 1911.

Our specimens by the courtesy of Dr. Sturgis.

EXTRA-LIMITAL

18. Didymium intermedium Schroeter.

• 1896. Didymium intermedium Schroet., Hedwigia, Vol. XXXV., p. 209.
• 1902. Didymium excelsum Jahn, Ber. Deut. Bot. Ges., XX., p. 275.

Sporangia clustered or gregarious, discoidal and umbilicate below, or lobed or convolute, greyish white, stipitate; stipe pale yellow, tapering upwards, stuffed with lime crystals, expanding into the yellowish, discoidal, recurving columella; capillitium colorless, more or less branching; spores dark purple-brown, irregularly reticulate, 9–12 µ.

Differs from D. squamulosum in the reticulate epispore. Brazil.

19. Didymium leoninum Berk. & Br.

• 1873. Didymium leoninum Berk. & Br., Jour. Linn. Soc., XIV., p. 83.
• 1876. Lepidoderma tigrinum Rost., App. to Mon., p. 23.
• 1909. Lepidodermopsis leoninus v. Höhnel, Sitz. K. Ak. Wiss. Wien, Math. Nat. Ks., CXVIII., 439.

Sporangia gregarious, sub-globose, covered more or less completely with white or yellowish deposits of crystalline lime, stipitate; stipes short, orange or brown, containing lime, enlarged to form the globose orange columella and often connected at base by a venulose hypothallus; capillitium of slender threads, anastomosing, colorless at the tips; spores violet-grey, minutely warted, 7–9 µ.

Like Lepidoderma tigrinum, but has different calcic crystals.

Java and Ceylon.[Pg 129]

3. Diderma Persoon

• 1794. Diderma Persoon, Röm. N. Mag. Bot., I., p. 89.
• 1873. Chondrioderma Rost. Versuch, p. 13, Mon., p. 167.
• 1894. Chondrioderma Rost., List., Mycetozoa, p. 75.
• 1899. Diderma Persoon, Macbr., N. A. S., p. 92.

Sporangia plasmodiocarpous or distinct, sessile or stipitate; the peridium as a rule double, the outer wall generally calcareous with the lime granules globular, non-crystalline, the inner wall very delicate and often, in the mature fructification, remote from the outer; columella generally prominent.

The genus Diderma is usually easy of recognition, by reason of its double wall, the outer, crustaceous, usually calcareous, and its limits remain substantially as originally set by Persoon. His definition is as follows:—

"Peridium ut plurimum duplex; exterius fragile; interius pellucens, subdistans. Columella magna, subrotunda. Fila parca latentia."—Syn. Meth. Fung., p. 168.

Rostafinski changed the name of the genus to Chondrioderma (chondri, cartilage), seemingly at De Bary's suggestion, and seems to have regarded Persoon's definition as applicable to those species only in which the wall is not only plainly double, but in which the two walls are as plainly remote from each other. More especially he esteemed a new generic name necessary, since he regarded several included species, as D. spumarioides, D. michelii, etc., monodermic.

Since it is doubtful whether any diderma is really monodermic, and since Persoon's definition in any case seems sufficiently elastic, we have seen no reason to discard the older name. Persoon's Diderma when established, l. c., included D. floriforme. He made some confusion in his later work by admitting some physarums. This induced Schrader to throw all the didermas into his new genus, Didymium.

According to the nature of the sporangial wall, the species fall rather naturally into two sections:—

1. Diderma effusum (Schw.) Morgan.

• 1831. Physarum effusum Schw., N. A. F., p. 257.
• 1896. Diderma effusum (Schw.) Morg., Jour. Cin. Soc., p. 71.
• 1899. Diderma effusum (Schw.) Morg., Macbr., N. A. S., p. 94.
• 1899. Diderma reticulatum Rost., Macbr., N. A. S., p. 95.
• 1911. Diderma effusum Morg., Lister, Mycetozoa, 2nd ed., p. 102.

Fructification plasmodiocarpous, reticulate, creeping, applanate and generally widely effused, white; the peridium thin, cinereous, covered[Pg 131] by a delicate, white, calcareous crust; the columella simply the base of the plasmodiocarp, thin alutaceous; the capillitium pale, consisting of short threads somewhat branched toward their distal extremities; spores smooth, pale violaceous, 8–10 µ.

This is Physarum effusum Schw., vid. N. A. F., No. 2297. It is reported by Morgan from Ohio, and we have one specimen from eastern Nebraska, so that it is probably of general distribution in the eastern United States.

This species was in the previous edition distinguished from the Rostafinskian P. reticulatum with spores a little smaller, 6–8 µ, and with a much stronger tendency to the formation of definite sporangia, elongate indeed and branching but often globose or depressed globose. This we may know as,

Var. reticulatum Rost.

• 1875. Chondrioderma reticulatum Rost., Mon., p. 170.
• 1894. Diderma reticulatum (Rost.) Morg., Jour. Cin. Soc., p. 71.

Sporangia gregarious, generally rounded, not much depressed, flat, sometimes, especially toward the margin of a colony, elongate, venulose or somewhat plasmodiocarpous, dull white, the inner peridium ashen or bluish, remote from the calcareous crust, which is extremely fragile, easily shelling off; columella indistinguishable from the base of the sporangium, thin, alutaceous; capillitium of short, generally colorless, delicate, sparingly branching or anastomosing threads perpendicular to the columella; spores black in mass, by transmitted light violet-tinted, smooth, 6–8 µ.

Perhaps our most common form. Found in fall on dead twigs, leaves, etc. Recognized by its rather large, white, depressed or flattened sporangia tending to form reticulations, and hence suggesting the name. The lines of fruiting tend to follow the venation of the supporting leaf; where the sporangium is round, the columella is a distinct rounded or cake-like body; where the fruit is venulose, the columella is less distinct.

By these rounded forms we pass easily, as by a gate, to D. hemisphericum, which, when wholly sessile, differs still in greater diameter of the sporangia and in having somewhat larger spores. Usually[Pg 132] in such case the compared colony will show somewhere a very short and stout but very real stipe supporting the discoid fruit.

Rostafinski divided the genus Chondrioderma, i. e. Diderma, into three sections:—

Monoderma to include those species in which the calcareous crust is less distinct or connate with the true peridium.

Diderma, in which the two structures were plainly separate.

Leangium, used as in the present work. In his first section Rostafinski placed C. reticulatum and C. michelii; in the second, C. difforme and C. calcareum.

Lister has examined Rostafinski's type of C. reticulatum and declares that it has the usual didermic characters. Hence there is no doubt that our small-spored American specimens are covered by Rostafinski's description, No. 72. On the other hand, Lister makes C. difforme (Pers.) Rost. a Didymium, by its crystalline coat. That species therefore is removed from consideration in this connection. C. calcareum remains as applicable to American forms having the spores 10–12 µ, but according to the author of the species the capillitium is abundant and definitive. Unhappily the type of C. calcareum is lost (Lister, Mon., p. 95), so that there is no other means of verification than the description and Rostafinski's figure. Under these circumstances we consider the name calcareum inapplicable to any American forms we have so far seen. See next species. As to the American species which have been distributed as C. calcareum (Lk.) Rost., they are, so far as seen, referable to D. reticulatum (Rost.), Morg. Here also belongs No. 1217, Ellis, N. A. F.

New York, Pennsylvania, Ohio, Iowa, Nebraska. Probably to be found throughout the eastern United States.

2. Diderma spumarioides Fries.

• 1829. Diderma spumarioides Fries, Syst. Myc., III., p. 104.
• 1833. Physarum stromateum Link., Handb., III., p. 409.
• 1876. Chondrioderma stromateum (Lk.) Rost., App., p. 18.

Sporangia sessile, crowded, spherical, or by mutual pressure irregular, white; the peridium plainly double, but the layers adhering, the outer more strongly calcareous, but very frail, almost farinaceous;[Pg 133] hypothallus more or less plainly in evidence, white or pale alutaceous; columella distinct, though often small, globose, yellowish; capillitium variable in quantity, sometimes abundant, brown, somewhat branching and anastomosing outwardly, the tips paler; spores minutely roughened, dark violaceous, about 10 µ.

This species has the outward seeming of a didymium, but is plainly different as that genus is here defined, since the calcareous crust, although inclined to be pulverulent, is made up of minute granules, not crystals, of lime. The hypothallus is sometimes hardly discoverable, anon well developed, out-spread, rugulose, far beyond the limits of the fructification. In his Monograph, p. 175, Rostafinski includes here Physarum stromateum Link. In the Appendix he is inclined to raise Link's form to the dignity of a distinct species, basing the diagnosis upon the superposition of the sporangia in certain cases, a feature entirely unknown to Link's description and of extremely uncertain value, since by their crowding the sporangia are liable always to be pushed above each other. We therefore regard C. stromateum (Link) Rost. as a synonym of the present species, as the description, Link, Handb., III., 409, indicates, so far as it goes.

3. Diderma simplex (Schroet.) Lister.

• 1885. Chondrioderma simplex Schroet., Krypt. Fl. Schles., III., 1, p. 123.
• 1911. Diderma simplex List., Mycetozoa, 2nd ed., p. 107.

"Plasmodium bright yellowish brown." Sporangia gregarious, sessile, globose or depressed globose, .3–.5 mm., or anon plasmodiocarpous, brown or brick-red when fresh, becoming paler, ochraceous, etc.; hypothallus everywhere in evidence; columella ill-defined; capillitium scanty, the threads delicate, pale, branching as they join the peridial wall; spores dull violaceous, slightly roughened, 8–10 µ.

A rather crude, primitive representative of this beautiful genus. The inner peridium seems to be lacking,—a comfort to Rostafinski! Rare. Our best specimens are from New Jersey, by courtesy of Dr. C. L. Shear. These went to fruit on leaves and branches of Vaccinium. It seems to affect the heather of Europe, moorland, etc. I have also specimens from the herbarium of the lamented Dr. Rex. These are more plasmodiocarpous, but open beautifully by a median[Pg 134] fissure as in Physarum sinuosum Bull. In no American gathering that I have examined does the capillitium show calcareous thickenings as described by the British text.

4. Diderma globosum Persoon.

Plate VII., Figs. 5, 5 a.

• 1794. Diderma globosum Pers., Röm. N. Mag. Bot., I., p. 89.
• 1875. Chondrioderma globosum (Pers.) Rost., Mon., p. 180.

Sporangia more or less closely gregarious, sessile, globose or by mutual pressure prismatic or polyhedral, white, the outer wall smooth, polished, crustaceous, fragile, far remote from the inner, which is thin, smooth, or rugulose, iridescent blue; hypothallus usually pronounced and spreading beyond the sporangia, sometimes scanty or lacking, columella variable, sometimes very small, inconspicuous, sometimes large, globose, ellipsoidal, even pedicellate; capillitium abundant, brown or purplish brown, branching and occasionally anastomosing to form a loosely constructed superficial net; spores globose, delicately spinulose, 8 µ.

This species seems rare in this country. We have specimens from Iowa. It is distinguished by small spores and generally snow-white color. Lister has thrown doubt upon Rostafinski's definition of this form—Mycetozoa, p. 78. Almost everything distributed in the United States under this name belongs in the next species. Reported also from Ohio,—Morgan. Washington. But:—it should be found in Europe, where first described!

There are two ways to meet the difficulty. In the first place it seems probable that a small-spored form really hides somewhere in Europe. The difference between the Monograph measurement and the size admitted for D. crustaceum Pk., evidently considered by Mr. Lister as type and so used in his illustration, Pl. 85, is too great to be esteemed merely an error. That added .3 (Rost.) indicates caution, the average of several measurements. Our D. globosum may represent what the Monograph describes.[32] In the second place we may as[Pg 135] American students mistake larger and more globular forms of something else, of D. spumarioides Fr., whose spores are but little larger; or of D. effusum (Schw.) Morg., where the flattened plasmodiocarps anon splatter out to globose drops of polished whiteness, and whose spores are 8 µ. But even here the chances of error are small. In the species last named the columella or sporangial base is alutaceous, not white; in Fries' species, while the columella if present may be white, the peridial walls are different, difficult to distinguish.

For these reasons, D. globosum Pers. may stand, waiting further light from Europe.

5. Diderma crustaceum Peck.

Plate VII., Fig. 7

• 1871. Diderma crustaceum Peck, Rep. N. Y. Mus., XXVI., p. 74.
• 1889. Chondrioderma crustaceum (Peck) Berl., Sacc., VII., p. 373.

Plasmodium at first watery, colorless, becoming at length milky white; sporangia closely crowded or superimposed, in a cushion-like colony, creamy white, globose, imbedded in the substance of the hypothallus, the outer peridium smooth, delicate, crustaceous, fragile, remote from the blue iridescent inner membrane; hypothallus prominent; columella variable, generally present, globose; capillitium dark-colored, the threads branching and combining to form a loose net; spore-mass black, spores by transmitted light dark violaceous, delicately roughened, 12–15 µ.

Common. Readily to be distinguished from the preceding by the larger spores and more crowded habit. New England west to Nebraska.

The didermas are generally delicately beautiful. The outer wall in the present species is like finest unglazed china, softly smooth, and yet not polished, often absolutely white, with porcellanous fracture. An inter-parietal space separates the outer from the inner wall, so that the former may be broken, bit by bit, without in the least disturbing the underlying structure. The inner wall is ashen or gauzy iridescent green, sending back all colors in reflected light. The spores are violet, deeply so when fresh, the capillitium strong and likewise tinted; the columella passing down and blending with the[Pg 136] common snow-white hypothalline base. The distinct habits of the two species are represented in Figs. 5 and 7. In the one the distinct sporangia are associated but not crowded; in the other all are massed together in quite æthalioid fashion, forming circumambient, chalky masses of considerable size, 2 or 3 cm., overcrowded, superimposed, where the sporangia are regular in shape and size by reason of mutual pressure. The plasmodium develops in forests and orchards, among decaying leaves, but is inclined to rise as maturity draws near, to ascend some twig erect, or the stem of a living plant to the height of several inches where the sporangia at length appear "heaped and pent", an encircling sheath, conspicuous after the fashion of a spumaria for which it is indeed sometimes mistaken.

6. Diderma lyallii (Massee) Macbr.

Plate XVIII., Figs. 5 and 5 a

• 1892. Chondrioderma lyallii Massee, Mon., p. 201.
• 1894. Chondrioderma lyallii Mass., List., Mycetozoa, p. 81.
• 1899. Diderma lyallii Mass., Macbr., N. A. S., p. 99.
• 1911. Diderma lyallii List., sub-species, Mycetozoa, 2nd ed., p. 105.

Sporangia obovate, more or less closely crowded, white, stipitate, about 1 mm. in diameter, the outer peridium firm, stout, encrusted, especially above, with granular masses of lime, the inner well developed, more or less cartilaginous, opaque, yellow or buff-colored; hypothallus well developed, venulose, white, passing up unchanged to form the short, stout stipe and lower outer peridium; columella prominent, half the height of the sporangium, brown; capillitium of short, brown threads, rigid, much branched, forming a net, widened irregularly and especially at the net-nodes; spore-mass black, spores by transmitted light bright brown, rough, 15–17 µ.

A very distinct species; large, fine, showy sporangia in more or less crowded clusters spring from a snow-white, common hypothallus. First reported from western Canada. Our first specimens were collected by the late Mr. Charles Irish, on the eastern slopes of the Sierras, in Nevada; now coming in abundantly from all the western mountains to the Pacific.[Pg 137]

7. Diderma testaceum (Schrad.) Pers.

Plate VII., 4, 4 a, and 4 b.

• 1797. Didymium testaceum Schrad., Nov. Gen. Plant., p. 25.
• 1801. Diderma testaceum Persoon, Syn., p. 167.
• 1873. Chondrioderma testaceum (Schrad.) Rost., Vers., p. 13.
• 1874. Diderma mariae-wilsoni Clinton, Rep. N. Y. Mus., XXVI., p. 74.
• 1899. Diderma testaceum (Schrad.) Pers., Macbr., N. A. S., p. 99.
• 1911. Diderma testaceum Pers., List., Mycetozoa, 2nd ed., p. 106.

Sporangia gregarious, sessile, depressed-spherical or sometimes elongate, small, 1 mm. or less, rose-white, smooth, the outer peridium crustaceous, rather thick and persistent, polished, slightly raised above the inner, which is dull ashen and more or less wrinkled; hypothallus none; columella prominent, hemispherical in the typical rounded forms, slightly rough, reddish or reddish alutaceous; capillitium usually abundant, of slender, delicate pale or colorless threads, little branched, and smooth; spores violaceous-brown, minutely roughened, 8–9 µ.

A very beautiful species occurring at the same time as the preceding and in similar situations. All our specimens from the west are on dead leaves of oak; some eastern gatherings are on moss. Easily recognized when fresh by its delicate pink or roseate color; weathered specimens are white, and might be confused with forms of D. reticulatum, but the sporangia in the present species are less flattened and only rarely in special situations run off to linear or plasmodiocarpous shapes characteristic of D. reticulatum.

Not common, although widely distributed from east to west. New England, New York, New Jersey, South Carolina, Ohio, Illinois, Iowa, Nebraska, California (Harkness), Washington, Oregon.

8. Diderma niveum (Rostafinski) Macbr.

Plate XVIII., Fig. 11 and 11 a

• 1875. Chondrioderma niveum Rost, Mon., p. 170.
• 1877. Diderma albescens Phillips, Grev., V., p. 114.

Sporangia gregarious, scattered, or more often crowded, sessile, depressed-spherical, sometimes ellipsoidal or elongate, white, the outer peridium crustaceous, chalky, smooth and fragile, the inner distinct, delicate, ochraceous; hypothallus scant or none; columella well developed, globose or hemispherical, orange-tinted or ochraceous; capillitium[Pg 138] abundant, made of threads of two sorts, some purplish or dusky, with pale extremities, uneven, others more delicate and colorless, and with wart-like thickenings, all sparingly branched; spores violet-brown, minutely roughened, 9–10 µ.

This species is not common. From Colorado we have fine specimens typical in every way. Specimens from Washington are flat so far as at present at hand; probably represent D. deplanatum (R.) List., which the last named author regards as varietal of the present species, entering it and D. lyallii as sub-species 2 and 1 respectively. D. deplanatum may perhaps be best so disposed of; but D. lyallii is distinguished at sight, as well as by microscopic characters, spores nearly twice as great, rougher and different in color.

9. Diderma cinereum Morg.

• 1894. Diderma cinereum Morg., Myx. Mi. Val., p. 70.

Sporangia gregarious, more or less crowded or even confluent, sub-globose, only slightly depressed, ashen white; the peridium not obviously double, very smooth and thin, rupturing irregularly; hypothallus an indistinct membrane or wholly wanting; columella large, globose or hemispheric, white, the surface granulose; capillitium of very slender colored threads, the extremities pellucid, more or less branched; spores violaceous, minutely warted, 9–11 µ.

Growing on old wood, leaves, etc. The sporangium .3–.5 mm., thin and smooth or rugulose. This elegant little species I know only from specimens received from Mr. Morgan. It seems to be closely related to D. spumarioides, from which it is distinguished by its color, darker, and its smoother, or less spinulose spores. The author compares the color and external appearance to that of P. cinereum,—Jour. Cin. Soc., XVI., p. 154.

Ohio, Pennsylvania.

10. Diderma hemisphericum (Bull.) Horne.

• 1791. Reticularia hemispherica Bull., Cham. de Fr., I., p. 93.
• 1829. Didymium hemisphericum (Bull.) Fr., Syst. Myc., III., p. 115.
• 1829. Diderma hemisphericum (Bull.) Horne., Fl. Dan., XI., p. 18.
• 1832. Didymium michelii Lib., Pl. Ard., No. 180.
• 1873. Chondrioderma michelii (Lib.) Rost., Fuckel, Sym. Myc., p. 74.

[Pg 139]

Sporangia gregarious, orbicular, discoid, depressed above and often umbilicate below, stipitate or sometimes sessile, the outer peridium white, fragile, crustaceous, soon breaking about the margins, closely applied to the inner, which is delicate, cinereous, and ruptures irregularly; stipe about equal to the diameter of the sporangium, 1 mm., rather stout, calcareous but colored, brownish or alutaceous, more or less wrinkled longitudinally, the wrinkles when present forming veins on the lower surface of the sporangium; hypothallus small; columella not distinct from the thickened brownish or reddish base of the sporangium; capillitium of delicate threads, mostly simple and colorless, often scanty; spores pale violaceous, nearly smooth, 8–9 µ.

A very well marked species, easily recognized, at least when stipitate, by its remarkable discoid or lenticular sporangia. After the spore-dispersal, the stipes are long-persistent, surmounted by a peculiar disk representing the consolidated columella, lower sporangial wall, and expanded stem-top. Sessile specimens are like similar forms of D. reticulatum, but in all the gatherings before us the stipitate type is at hand to reveal the identity of the species.

Rostafinski's figures, 131, 146, 149, and 150, adapted from Corda, exaggerate the hypothallus, but otherwise leave nothing to be desired.

As to synonymy, Bulliard has plainly the priority. His figure, t. 446, Fig. 1, can refer to nothing else, especially reënforced as it is by Sowerby, Eng. Fung., t. 12.

Rather rare on fallen stems of herbaceous plants, but widely distributed, New England to Oregon and Washington.

11. Diderma sauteri (Rost.) Macbr.

• 1875. Chondrioderma sauteri Rost., Mon., p. 181.
• 1891. Chondrioderma aculeatum Rex, Proc. Phil. Acad., p. 390.

Sporangia scattered, gregarious, sessile, lenticular or hemispherical, flattened above and sometimes concave or umbilicate below, dusky or yellowish white, the outer peridium papyraceous, thin, occasionally wrinkled, rupturing irregularly, remote from the inner, which is thin, delicate, semi-transparent, grayish, rarely iridescent; hypothallus none; columella irregular, sometimes small and hardly evident, rugose, with spine-like processes, the persisting bases of the capillitial[Pg 140] threads, reddish brown; capillitium scanty, white, or colorless, simple or sparingly branched; spores dark violaceous, spinulose, 12–13 µ.

This is Chondrioderma aculeatum Rex, Proc. Acad. Nat. Sci. Phil., 1891, p. 390. After careful comparison of specimens and various descriptions, especially that of Rostafinski with the type specimens of Dr. Rex, I am constrained to concur with Lister in adopting Rostafinski's name. The sporangia in the type specimens (Rex) are on moss, borne at the extreme tips of acuminate or aculeate leaves, so that at first sight they appear stipitate.

Apparently rare. Maine, New York.

12. Diderma cor-rubrum Macbr. n. s.

Plate XVIII., Fig. 2

Sporangia gregarious clustered, small .5–.7 mm., sessile corrugate-plicate, especially above, snow-white, the outer peridium cartilaginous polished without and within, the inner delicate, evanescent; columella well developed, globose or clavate, anchored by several stout transverse trabeculæ to the peridial wall, papillate, deep-red as is the peridium especially below; capillitium very delicate, sparingly branching, colorless; spores verruculose, fuliginous tinged with red, about 12 µ.

This curious but elegant little species is represented by a single colony collected by Professor Morton Peck in Iowa. It resembles D. sauteri but is distinguished by the plicate white wall, the stout columella with its lateral extensions, as by the more delicate spores. On rotten wood.

13. Diderma ochraceum Hoffm.

• 1795. Diderma ochraceum Hoffm., Deutsch. Fl. Tab. 9, 2, b.
• 1911. Diderma ochraceum Hoffm., List., Mycetozoa, 2nd ed., p. 109.

Sporangia gregarious or clustered, .7–1 mm., sessile, globose or sometimes plasmodiocarpous, ochraceous yellow; outer wall cartilaginous with yellow deposits of lime, the inner also yellow, adherent or free; columella not distinct; capillitium simple or branching, purple-brown, hyaline at base; spores spinulose, purplish-grey, 9–11 µ.

Mr. Lister reports this species from Massachusetts.[Pg 141]

14. Diderma roanense (Rex) Macbr.

• 1893. Chondrioderma roanense Rex, Proc. Phil. Acad., p. 368.

Sporangia scattered, discoidal, thin, flattened or slightly convex above, plane or plano-concave below, umber-brown, stipitate, the outer peridium smooth, brittle, rupturing irregularly, the basal fragments somewhat persistent, concrete with the inner peridium, which is pure white, except near the columella, and punctate; stipe short, variable, longitudinally ridged, jet-black; hypothallus none; columella flat, discoidal, pale ochraceous; capillitium sparse, white or colorless, composed of simple, rarely forked, sinuous threads occasionally joined by lateral branches; spores dark violaceous, distinctly warted, 12–14 µ.

This species is readily distinguished by its color. The sporangia, found on rotten wood, are large, 1 mm., brown, and have thick, persistent walls. Dr. Rex considered that the species differs from other related forms not only in color, but in the well-marked discoidal columella and the jet-black irregular stipe. It is perhaps most nearly related to the following species.

Tennessee.

15. Diderma radiatum (Linn.) Morg.

Plate XVIII., Fig. 8

• 1753. Lycoperdon radiatum Linn. (?) Sp. Pl., 1654.
• 1797. Didymium stellare Schrad., Nov. Gen. Pl., p. 21.
• 1801. Diderma stellare (Schrad.) Persoon, Syn., p. 164.
• 1875. Chondrioderma radiatum (Linn.) Rost., Mon., p. 182.
• 1894. Diderma radiatum (Linn.) Morg., Jour. Cin. Soc., p. 66.
• 1899. Diderma stellare Schrad., Macbr., N. A. S., p 104.
• 1911. Diderma radiatum List., Mycetozoa, 2nd ed., p. 112.

Sporangia scattered, depressed-globose, sometimes also flattened below, stipitate, smooth or slightly corrugate, ashen or brownish, about 1 mm. in diameter, the peridium dehiscing irregularly or somewhat radiately from above downwards, the segments reflexed, the inner layer not distinguishable, or inseparable; stipe short, stout, brownish, sometimes almost lacking; hypothallus not conspicuous, but sometimes sufficient to connect the bases of adjacent stipes; columella large, hemispherical or globose, pallid or yellowish; capillitium abundant, of slender generally simple, colored threads, paler at the furcate tips; spores dark violaceous, minutely roughened, 8–11 µ.[Pg 142]

Rare on rotten logs in the forests; September. Easily recognized by the short-stiped, ashen sporangia which before dehiscence indicate by delicate tracings the lines which subsequent cleavage is to follow. In texture the peridium resembles that of D. floriforme.

Pennsylvania, Ohio, Iowa, Virginia, Colorado, Washington, Oregon; Europe generally.

The Linnæan description on which to base the specific name D. radiatum is wholly inadequate. It appears also by the testimony of Linné fils, that L. radiatum Linné is a lichen! and the name is so applied by Persoon. But in the Linnæan herbarium preserved at London, teste Lister, the original type of Lycoperdon radiatum L. may yet be seen! to the confusion of fils, Persoon, and other followers of Schrader all, and our stellar species becomes radiate now, let us hope for long!

16. Diderma trevelyani (Grev.) Fr.

• 1825. Leangium trevelyani Grev., Scot., Cr. Fl., Tab. 132.
• 1829. Diderma trevelyani (Grev.) Fr., Syst. Myc., III., p. 105.
• 1875. Chondrioderma trevelyani (Grev.) Rost., Mon., p. 182.
• 1877. Diderma geasteroides Phill., Grev., V., p. 113.
• 1877. Diderma laciniatum Phill., Grev., V., p. 113.

Sporangia scattered, globose or nearly so, smooth or verruculose, reddish-brown or rufescent, sessile or short-stipitate, the outer peridium firm, splitting more or less regularly into unequal, revolute, petal-like lobes which are white within, the inner not distinguishable as such; stipe, when present, equal, furrowed, concolorous; columella small or none; capillitium abundant, the threads rather rigid, purple or purplish brown, branching and anastomosing, more or less beaded; spores dark, violaceous brown, spinulose, 10–13 µ.

In 1876, Harkness and Moore collected in the Sierra Nevada Mountains of California, forms of Diderma which are described by Phillips, Grev., V., p. 113, as D. geasteroides and D. laciniatum. English authorities who have examined the material agree that the forms described constitute but a single species, and Lister makes them identical with D. trevelyani (Grev.) Fr. Rostafinski's figures, 161, 162, are a curious reproduction, evidently, of Fried. Nees von Esenbeck's, Plate IX., Fig. 4. Massee describes a columella; Lister says[Pg 143] there is none. What may occasion such divergence of statement none may say; such forms as come in so far from our western mountains have no columella.

17. Diderma asteroides List.

Plate XVIII., Figs. 3, 3 a

• 1902. Diderma asteroides List., Jour. Bot., XL, p. 209.
• 1911. Diderma asteroides List., Mycetozoa, 2nd ed., p. 113.

Sporangia globose or ovoid-globose, the apex more or less acuminate, sessile, sometimes narrowed at the base to a short, thick stalk, brown or chocolate tinted, marked at the apex by radiant lines, and at length dehiscent by many reflexing lobes revealing the snow-white adherent inner peridium on the exposed or upper side; columella also white, globose or depressed-globose; capillitium generally colorless, somewhat branched, especially above; spores dark violaceous, verruculose, 10–12 µ.

Oregon, the Three Sisters Mountains; Colorado; California.

A very beautiful species, recognizable at sight; when unopened, by the peculiar chocolate brown, the sporangia smaller than in D. radiatum. When opened, the snow-white flower-like figure, flat against the substratum, is definitive. Very near number 16 preceding; the dehiscence more regular.

18. Diderma floriforme (Bull.) Pers.

Plate VIII., Figs. 1, 1 a, 1 b.

• 1791. Sphaerocarpus floriformis Bulliard, Champ., p. 142, t. 371.
• 1794. Diderma floriforme (Bull.) Persoon, Röm. N. Mag. Bot., p. 89.

Sporangia crowded, generally in dense colonies, globose, smooth, ochraceous-white, stipitate, the peridium thick, cartilaginous, splitting from above into several petal-like lobes, which become speedily reflexed exposing the swarthy spore-mass, the inner peridium not discoverable, inseparable; stipe concolorous, about equal to the sporangium; hypothallus, generally well developed, but thin, membranaceous, common to all the sporangia; columella prominent, globose or cylindric, often constricted below, and prolonged upward almost to the top of the spore-case; capillitium of slender, delicate, sparingly[Pg 144] branched threads; spores dark violaceous-brown, studded with scattered warts, 10–11 µ.

Not uncommon, especially on rotten oak logs. Easily recognized by the peculiar form of the fruit, spherical before dehiscence, floriform after. Unlike most species, this form often fruits in dark places, in the interior of a log, even in the ground.

New England, Ontario to Iowa and Nebraska, and south.

19. Diderma rugosum (Rex) Macbr.

Plate XVIII., Fig. 10.

• 1893. Chondrioderma rugosum Rex, Proc. Phil. Acad., p. 369.

Sporangia gregarious, scattered, white or ashen, rugulose over the whole surface, the ridges marking the lines of subsequent rupture or dehiscence, the peridium thin papyraceous, stipitate; stipe well developed about equal to the sporangium, subulate, almost black; hypothallus none; columella distinct, generally white, sometimes small, globose, sometimes penetrating the sporangium, to one-half the height; capillitium white or colorless, the filaments freely forked and combined by lateral branches into a loose network attached to the columella and basal wall below and the upper sporangial wall above; spores violaceous-brown, warted, 8–10 µ.

This species is well designated rugosum, and is recognizable at sight by its wrinkled, areolate surface. Related to D. radiatum in the prefigured dehiscence, but otherwise very distinct. Liable to be overlooked as a prematurely dried physarum. Rare. Plasmodium gray.

North Carolina, Iowa.

4. Lepidoderma DeBary

• 1858. Lepidoderma DeBy., MS. Rost., Versuch, p. 13.

Sporangia stalked or sessile; peridium cartilaginous, adorned without with large calcareous scales, superficial or shut in lenticular cavities; capillitium non-calcareous.[33]

[Pg 145]

Key to Species of Lepidoderma

1. Lepidoderma tigrinum (Schrad.) Rost.

Plate XIV., Fig. 7.

• 1797. Didymium tigrinum Schrad., Nov. Gen. Plantarum, p. 22.
• 1873. Lepidoderma tigrinum (Schrad.) Rost., Versuch, p. 13.

Sporangia scattered, rather large, hemispherical-depressed, stipitate, umbilicate beneath, the peridium shining, olivaceous or purplish, tough, covered more or less abundantly with angular scales; the stipe stout, furrowed, dark brown, but containing calcareous deposits withal, tapering upward, and continued within the peridium as a pronounced more or less calcareous columella; hypothallus more or less prominent, yellowish or brownish; capillitium dark, purplish-brown, of sparingly branching threads radiating from the columella; spores dull purplish-brown, minutely roughened, 10–12 µ.

A singular species, rare, but easily recognized by its peculiar, placoid scales, large and firmly embedded in the peridial wall. The internal structure is essentially that of Diderma or Didymium. The species occurs in hilly or mountainous regions, on moss-covered logs. The plasmodium pale yellow, some part of it not infrequently remains as a venulose hypothallus connecting such sporangia as are near together.

New England to Washington and Oregon; Vancouver Island.

2. Lepidoderma carestianum (Rabenh.) Rost.

• 1862. Reticularia carestiana Rabenh., MS. Fung. Eur. exsic., No. 436.
• 1875. Lepidoderma carestianum (Rabenh.) Rost., Mon., p. 188.
• 1891. Amaurochaete minor Sacc. & Ell., Mich., II., p. 566.

[Pg 146]

Fructification in the form of flat, pulvinate plasmodiocarps, or, anon, sporangiate, the sporangia sessile, sub-globose, ellipsoidal, elongate, irregular, confluent, yellowish-grey, the peridium covered more or less completely with dull white, crystals or crystal-like scales; columella, where visible, yellowish-brown, calcareous; capillitium, coarse, rigid, more or less branched and united, or colorless, delicate, forming a definite net; spores distinctly warted, purple 10–12 µ.

This is a most remarkable species. The sporangiate forms little resemble those distinctly plasmodiocarpal. In the former the calcic scales and crystals are distinct and quite as in L. tigrinum; in the latter they are cuboid, irregular. The wall of the peridium in the plasmodiocarps at hand is black, and the covering accordingly shows white; in the sporangial forms the wall is brown, and the scales have a yellow tinge as if tinged with iron. In the sporangial presentation the capillitium is intricate delicate; in the plasmodiocarp, rigid, dark-colored, etc. This looks like a didymium and in so far justifies the opinion of earlier students. Fries, of course, includes all these things with the didymiums, and D. squamulosum probably often sheltered them under extended wing.

Didymium granuliferum Phill., Grev., V., p. 114, from California is by European authors referred here. The capillitium carries calcareous crystalline deposits in special vesicles and the spores show remarkable variation in unusual size—15–30 µ.[1]

Should probably be entered Lepidoderma granuliferum (Phill.) Fr., spores 15–18 µ.[34]

Utah,—Harkness.

3. Lepidoderma chailletii Rost.

Plate XVIII., Figs. 6, 6 a, 6 b.

Sporangia distinct, coalescent or plasmodiocarpous, large, when isolated 1–1.5 mm., dull drab in color, very sparsely sprinkled with white tetrahedral or irregular scales; the peridium thin, more or less translucent, rugulose, dull brown, persistent; columella none; capillitium abundant, under the lens purple-brown, sparingly branched,[Pg 147] even, stout, rigid, no calcareous deposits nor vesicles; spores 8–10 µ, minutely warted, fuliginous.

Yosemite Cañon, California, Prof. B. Shimek.

This is, no doubt, similar to L. carestianum but differs in the size and habit of the sporangia, and in the fact that the capillitium is uniform throughout, whatever the style of fructification, and in the size, color, and surface characters of the spore.

Evidently not Didymium granuliferum Phill. Both will, no doubt, be again collected, and we shall then have much needed light.

Nor is this quite Rostafinski's species as cited. The spores are much smaller; Rostafinski says 10–12 or more, and calls for a distinctly netted capillitium, the surface strongly marked by abundant calcareous crystals. Ours may be a different thing.

5. Colloderma G. Lister

• 1910. Colloderma, Jour. of Botany, XLVIII., p. 312.

Peridium double; the outer gelatinous, the inner membranaceous; capillitium intricate, limeless.

Colloderma oculatum (Lipp.) G. Lister.

• 1894. Didymium oculatum Lipp., Verh. Zo-Bot. Ges. Wien, XLIV., p. 74.
• 1910. Colloderma oculatum (Lipp.) G. List., Jour. Bot., XLVIII., p. 312.

Sporangia gregarious, globose, or sub-globose, sessile or short-stipitate, olivaceous or purplish-brown, smooth and shining, the outer peridium gelatinous, thickened by moisture, hyaline; stipe dark brown; columella none; capillitium as in Didymium purplish-brown, colorless at the tips; spores spinulose, fuscous, about 12 µ.

New Hampshire, Europe.

Our specimens from the late Dr. W. G. Farlow who collected it in New Hampshire. Swollen by immersion in water the sporangia take on an eye-like appearance, oculate, etc.

EXTRA-LIMITAL

Physarina von Höhnel.

• 1909. Physarina von Höhnel, Akad. Wiss. Wien; Math-nat. KL., CXVIII., p. 431.

[Pg 148]

Sporangium wall rough with blunt spine-like processes, otherwise as Diderma.

One species, op. cit., p. 432, P. echinocephala v. Höhn.

Java. Might as well be called Diderma echinocephalum, one would think. Structure is that of Leangium. The striking character is a surface modification of the outer peridium, according to the description.

Order II

STEMONITALES

Capillitium present, thread-like, arising in typical cases from a well-developed columella; spores in mass, black or violet-brown, more rarely ferruginous.

Key to the Families of Stemonitales

A. AMAUROCHÆTACEÆ

Fructification æthalioid, an inch or two in diameter, in form varying with the habitat and place; capillitium dendroid, consisting of rather stout branches which rise irregularly more or less vertically from the hypothallus, branch repeatedly, often anastomose to form a network, especially toward the periphery; spores black.

A single genus—

1. Amaurochæte Rostafinski

• 1873. Amaurochaete Rost., Versuch., p. 8.

The genus Amaurochaete as defined by Rostafinski and the genus Reticularia as represented by R. lycoperdon Bull. stand, the expression, perhaps, of not dissimilar histories. Whether in regressive or[Pg 149] progressive series, each to-day presents a case of arrested development. Each in æthalioid fructification, reveals a mass of involved individual (?) sporangia, so imperfectly developed that their outlines can be inferred rather than anywhere, with absolute definiteness, certainly ascertained. Perhaps, because similar sporangia in the group to which either belongs, do come under other circumstances, to more perfect individual form and function—perhaps for this reason we may look upon these æthalia as exhibiting a suspended performance; the sporangia have failed to go forward to what was evidently a possible, though apparently not an essential destiny in form and figure. For the care and dispersal of the spores, achievement must surely be somewhat impaired. Whatever the measure of such inefficiency, among the Stemonitales Amaurochaete shows the acme, as Reticularia among the brown-spored forms.

In Amaurochaete the individuality of anything like separate sporangia is less clear. The view afforded, however, by a good vertical section of a well-developed colony or cushion is interestingly arborescent. Ragged, dendroid stems arise, dissipated above into a network most intricate, a "pleached arbor" if you please. The resemblance of the overhead net to that presented by a stemonitis or comatricha is very striking.

Key to the Species of Amaurochæte

1. Amaurochæte fuliginosa (Sowerby) Macbr.

Plate V., Figs. 8, 8 a.

• 1803. Lycoperdon fuliginosum Sow., Eng. Fung., t. 257.
• 1805. Lycogala atrum, Alb. & Schw., Consp. Fung., p. 83.
• 1875. Amaurochaete atra (Alb. & Schw.) Rost., Mon., p. 211.

Fructification aethalioid, varying in form and size, if on the upper side of the substratum, pulvinate, if below pendent and almost stipitate, covered with a delicate cortex, at first shining, soon dull, black, fragile, and early dissipated; hypothallus long-persisting, supporting the capillitium, which is extremely variable, irregular, and for its[Pg 150] perfection dependent upon the form assumed by the æthalium, and the conditions of weather, etc., under which it matures, sometimes, especially when prostrate, in a very much depressed æthalium, spreading into long fibrous threads, again under better conditions rising in columella-like forms, supporting a peripheral net; spores dark brown or black, irregularly globose, spinulose, 12.5–15 µ.

Common in Europe, and probably not uncommon in this country wherever pine forests occur. Specimens before us are from New England and New York, Ohio, Carolina, Colorado. Canada.

Sowerby, in his comment on plate 257, Eng. Fungi, says: "It appears to consist of branching threads affixed to the deal and holding a dense mass of sooty powder. Over the whole is a thin, deciduous pellicle." This description seems to be applicable to nothing else. The figure amounts to little. Fries recognizes the English description, as does Rostafinski, but both authors adopt the later name given by Albertini and Schweinitz, simply because of the excellent detailed description found in the Conspectus.

2. Amaurochæte tubulina (Alb. & Schw.) Macbr.

Plate XX., 6 and 6 a.

• 1805. Stemonitis tubulina (Alb. & Schw.), Cons. Fung., p. 102.
• 1825. Lachnobolus cribrosus Fr., Syst. Orb. Veg., p. 14.
• 1912. Amaurochaete cribrosa (Fr.) Macbr., Com. in litt. to Herbaria, Harvard, etc.[35]
• 1917. Amaurochaete cribrosa (Fr.) Sturg., G. Lister, Jour. Bot., LVIII, p. 109.

Plasmodium at first transparent then white then rosy, ashen or grey finally deepening to jet-black; the æthalium even, thin, variable in extent from one to ten centimeters, covered by a distinct but thin transparent cortex, papillate, extended laterally but a short distance beyond the fructification, fragile, soon disappearing; hypothallus long-persistent, thin, silvery, supporting the capillitium as if by stipes, short slender columns, irregular plates, expansions, etc.; the capillitium an intricate network, very abundant, elastic, on fall of the peridium appearing like tiny tufts of wool, the meshes large, but formed as in Stemonitis, persistent, dull black; spores, under the lens, dull olivaceous black, minutely roughened, 12–14 µ.

[Pg 151]

This species differs from the preceding, already well known, especially in the capillitial characters. In the older species the capillitial branches fray out, and are only sparingly united into a net extremely lax. In the present form the net is the thing, common to all sporangia. The total effect is to lend to the blown-out æthalium a woolly appearance, entirely unlike that of its congener under the same conditions. But until fructification is quite mature, the presence of the collaborating sporangia below is indicated, suggested, by the papillose upper surface.

The amaurochetes are remarkable in that they appear upon coniferous wood, logs or lumber, to all appearance undecayed. The species just described developed abundantly in August on the recently decorticated logs of Pinus ponderosa, on the south-western slopes of Mt. Rainier, Washington. In logging operations in the locality referred to, the trees are felled often at considerable distance from the mill. They are not infrequently large, 75–120 cm. in diameter. The logs are dragged along the ground, the transportation facilitated by removal of the bark from the new fallen trunk. In a few weeks' time, affected by alternate rain and sun, the whole surface becomes marked with hundreds of minute, almost invisible cracks, and it is in the larger of these that the plasmodium of the present species has its habitat. Hardly any mycologic phenomenon is more surprising than to see plasmodia rising to fructification, scores at a time, upon a surface, new and white, showing otherwise no evidence of any decomposition. Doubtless the persisting cambium, the unused starches, sugars, the wood of the season yet unlignified, afford easily accessible nutrition.

When this form was first examined in the laboratory its distinctness was immediately seen. It was without doubt Fries' cribrose reticularia; nobody questions that. Under this name, citing Fries' description, specimens were sent out to herbaria as Harvard. Further study of the records, however, soon convinces one familiar with the ontogeny of the case that we are here face to face with the species, described by Alb. & Schw. in their fine Conspectus. Their account of the form, evidently often taken and now described with great care, is entirely clear when read in presence of the facts. It is here submitted,[Pg 152] as less easy of access but essential, if the reader would appreciate the present disposal of the species.

"S. Tubulina NOBIS

"S. magna pulvinata subhemisphaerica, stylidiis gregariis circinantibus, capillitiis elongatis cylindraceis in massam pulveraceam fuscam connatis, apicibus obtusis, prominulis, lucidis nigris.

"The size indeed, the circumscribed form, the capillitiums conjoined into a single body—indue this (form) with an appearance peculiar to a degree; however, should anyone prefer to call it a very remarkable variety of the preceding (S. fasciculata), we shall not strenuously refuse. At first glance it looks like a tubulina. After the fashion of its kind, the beginning is soft and milky. The diameter generally an inch and a half to two inches, the height four to six lines; the form perfectly round, or more rarely somewhat oblong. The hypothallus, stout, pellucid silvery, betimes iridescent, when turned to the light, easily separable from the substratum, bears the columellae, dusky, thin, hair-like, aggregate and yet entirely free, and everywhere circinately convergent, depressed by the superimposed burden, hence decumbent: ... the capillitium loosely interwoven, coalesces to a common mass whose smooth and shining surface shows above, regularly disposed minute papillae, the apices of individual sporangia.

"Far from infrequent, on decorticate pine, of Lycogala atrum a constant companion"!

It goes of course without saying, that for the authors quoted, Lycogala atrum is Amaurochaete atra Rost. A. fuliginosa (Sow.) of more recent students, described and perfectly figured in the volume cited.

It is surprising that they did not enter the present species also as a lycogala. But the stemonitis relationship this time impressed them rather than the æthalial; besides they were misled by the S. fasciculata of Gmelin and Persoon, a composite which the genius of Fries hardly availed to disentangle twenty-five years later.

The last named author, as we see, wrote first Lachnobolus, then Reticularia. He calls the interwoven capillitium—lachne, wool, a[Pg 153] "pilam tactu eximie elasticam," etc. He read the description in the Conspectus, but carried away the stemonitis suggestion dominant there, as we have seen, put S. tubulina A. & S. as an undeveloped phase of S. fusca, which, of course, it is not. It needed not the authority of Rostafinski, Mon., p. 197, to assure us this. The earlier authors describe the species in course of development to complete maturity, and clinch the story by declaring the form a constant companion of the commonly recognized amaurochete, so fixing the relationship for us by habitat also.

These men made a mistake, of course, in placing their species among the stemonites at all. They did much better however than Fries who called it a reticularia. It was also a mistake to cite S. fasciculata,—the small fasciculate tufts of S. fusca and S. axifera offering by the aggregate habit only faint resemblance,—a possible refuge for those who would prefer another disposition of their species distinct (aliena) though it is.

Since Fries' day the species has been overlooked although the genus has received more than once attention. Zukal Hedwigia, XXXV., p. 335, describes A. speciosa as a new species. This Saccardo writes down, Syll. Fung., VII., p. 399, S. tubulina A. & S., admitting, however, at the same time, that as fine an authority as Raciborsky refuses to call Zukal's species either a stemonite or an amaurochete, thinks it deserving generic appellation of its own.

However, A. speciosa Zuk. need not here concern us. Neither in his description nor figures does Zukal at all approach the form we study. His species is not an amaurochete; the size of the spores suggest that, to say nothing of the capillitial structure.

In the same volume VII., the distinguished author introduces another amaurochete, A. minor Sacc. & Ellis, Mich. II., p. 566. This is American; sent from Utah by our famous pioneer collector Harkness. A specimen is before us: it is a lepidoderma! in shining, scaly armor dressed; vid. under L. carestianum.

Since the distribution of Washington material, as mentioned, our species reappears at various points in western Europe, points in England, etc., and will no doubt now share, hereafter as a century ago, the habitat so long conceded to the long familiar older type.[Pg 154]

B. STEMONITACEÆ

Capillitium abundant, springing usually as dissipating branches from all parts of the columella; the sporangia generally definite and distinct, though sometimes closely placed and generally rising from a common hypothallus.

Key to the Genera of the Stemonitaceæ

1. Brefeldia Rostafinski

• 1873. Brefeldia Rost., Versuch, p. 8.

Sporangia occupying in the æthalium several layers, those of the median, and especially of the lowest layers, furnished with columellæ which blend beneath; capillitium threads in the lowest layers arising from the columella, in the upper extending radiately between the individual sporangia, and united at the sporangial limits by means of rather large inflated sacs.

The genus Brefeldia is, like some others, difficult to dispose of in any scheme of classification where linear sequence must be followed. Rostafinski placed it in an order by itself. Its relationships are on the one hand with Amaurochaete and Reticularia, and on the other with the Stemonitales, though easily distinguished from either. It is intermediate to Amaurochaete and Stemonitis, and withal, as it appears to us, a little nearer the latter, as the limits of the individual sporangia are in Brefeldia pretty well defined.

1. Brefeldia maxima (Fr.) Rost.

Plate V., Figs. 7, 7 a, 7 b, and Plates XXI., XXII.

• 1825. Reticularia maxima Fries, Syst. Orb. Veg., I., p. 147.
• 1875. Brefeldia maxima (Fr.) Rost., Versuch., p. 8.

Æthalium large, four to twenty cm, papillate above, violet-black at first, then purple or purple-brown, developed upon a widespread,[Pg 155] silver-shining hypothallus; sporangia in favorable cases distinct, indicated above by the papillæ; columellæ obscure, black; capillitium abundant, the threads uniting by multifid ends to surround as with a net the peculiar vesicles; spore-mass dark violet-black, the individual spores paler by transmitted light, distinctly papillose, 12–15 µ.

A very remarkable species and one of the largest, rivalled by Fuligo only. To be compared with Reticularia, which it resembles somewhat externally, and with some of the larger specimens of Enteridium. The plasmodium at first white with a bluish tinge is developed abundantly in rotten wood, preferably a large oak stump, and changes color as maturity comes on, much in the fashion of Stemonitis splendens, leaving a widespread hypothallic film to extend far around the perfected fruit-mass. In well-matured æthalia, "Jove favente," the sporangia stand out perfectly distinct, particularly above and around the margins. Closely and compactly crowded, they become prismatic by mutual pressure, and attain sometimes the height of half an inch or more. In the centre of the fructification, next the hypothallus, the sporangia are very imperfectly differentiated. Many are here horizontally placed, and perhaps supplied with an imperfectly formed peridium,—if so are to be interpreted the lowest parts of the capillitial structure, the long, branching, ribbon-like strands which lie along the hypothallus. Some of these branch repeatedly with flat anastomosing branchlets, ultimately fray out into lengthened threads, and perish after all the superstructure has been blown away. From every part of the structure so described, but more especially from the margins, are given off in profusion the strange cystiferous threads, so characteristic of this genus. These are exceeding delicate filaments, attached at one end, it may be, to a principal branch, at the other free or united to a second which again joins a third, and so looping and branching, dividing, they form a more or less extended network, a capillitium in which are entangled the myriad spores. Each filament bears at its middle point (or is it the meeting point of two?) a peculiar plexus which embraces several large cysts or vesicles whose function or further homology does not readily appear.

From the base of the fructification rise also ascending branches which are black, terete, and not infrequently branched as if to form[Pg 156] the capillitium of a stemonitis. These ascending branches are in many cases, probably in all, real, though as yet imperfectly developed, columellæ. They rise, at least in many cases, directly from the hypothallus, each is central to an individual sporangium, rises to about two-thirds its height, but never attains the summit. The sporangia are so crowded that many are choked off below, never reach the top of the æthalium. In such cases the columella may cease at the sporangium-top. The columella bears cystiferous threads sparingly, if at all; nevertheless these abound in the peripheral portions of the sporangium all the way up, and are especially noticeable beyond the level of the top of the columella. Many are so arranged that the plexus with its vesicles occupies a place in the plane separating adjacent sporangia, suggesting the possibility that we have here to do with an imperfectly developed surface-net and peridium. In this view the cysts would represent the meeting-point of two opposite radial capillitial threads rather than the middle of one. This accords with Rostafinski's observations and drawings. The cysts, then, belong morphologically to the peridium or sporangium wall. It is a stemonitis whose sporangia have never been perfectly differentiated, a case of arrested development. See further under Stemonitis confluens.

Rostafinski really offers the first definitive description. Fries probably distinguished it, but his description would not indicate the fact except for the added note wherein appears the reason for discarding an apparently older name, viz., that given by Link. But neither Link nor Sowerby distinguished by description or figure Brefeldia from Amaurochaete.

Throughout the northern forest; Maine to Vancouver Island: not common.

2. Stemonitis (Gleditsch) Rost.

• 1753. Stemonitis Gleditsch, in part, Meth. Fung., p. 140.
• 1873. Stemonitis (Gleditsch) Rost., Versuch, p. 7.

Sporangia distinct, though often closely aggregate, cylindric, stipitate; columella prominent; capillitium well developed by repeated lateral and apical branching of the columella, at length assuming at the surface the form of a distinct net which supports an evanescent peridium.[Pg 157]

The genus is marked by its surface-net supported at the tips of the dichotomously branched divisions of the columella. Over the net is spread, theoretically at least, the peridial film supported by very short points projecting from the net,—the peridial processes; the peridium, however, is seldom seen; in some cases, certainly, is never developed. Rostafinski first defined the genus as employed by recent writers. Gleditsch simply renamed Micheli's Clathroidastrum; all writers subsequent included species of other genera.

The taxonomy of this genus is of the most difficult. Macroscopic, defining characters are few, and even these sometimes uncertain. Microscopic distinctions also tend to be illusive, variable in such fashion that often at the critical point the most exact description fails. All that may be done at present is to recognize two or three definite types and then cautiously differentiate among these with the light we have, until more general study of the group brings to service a wider range of observation with more comprehensive record on which judgment may better be sustained.

We have before us many and beautiful forms of this genus yet unstudied. Some of these doubtless have already found place in our growing taxonomic literature; some apparently undescribed; all to wait wider leisure or perhaps a younger hand.

The entire life-history of every form is none too much if we would set out with any hope of accuracy the genetic relationships for which taxonomy stands. Recently European students are making the color of the plasmodium a basis for species-discrimination, which is good so far. But plasmodic characters are at present unserviceable generally, for two reasons; they vary in the same species; and unfortunately, when most needed, they are unknown and inaccessible. The student is generally confronted by forms mature, the plasmodic stage already past.

Key to the Species of Stemonitis

1. Stemonitis confluens Cooke & Ellis.

Plate XI., Figs. 4, 4 a, 5.

• 1876. Stemonitis confluens Cke. & Ell., Grev., V., p. 51.
• 1894. Stemonitis splendens var. confluens Lister, Mycet., p. 112.
• 1899. Stemonitis confluens Cke. & Ell., Macbr., N. A. S., p. 114.
• 1911. Stemonitis confluens Cke. & Ellis, List., Mycet., 2nd ed., p. 147.

"Sporangia fasciculate, confluent on a persistent hypothallus, dark fuscous; peridia very fugacious; stipes united at the base, erect, furcate; spores large, brown, globose. On oak bark.

"The stems are branched in a furcate manner and confluent at the base, forming a compact tuft. The capillitium is membranaceous at the angles; spores very large compared with allied species, being 12 µ. The specimens were too fully matured for more satisfactory description."[Pg 159]

Such is the original description of this unique and interesting species. The sporangia occur in close-set tufts or clusters, are distinct, separate at their tips and bases only; perhaps not always at base. The capillitium rises by branching from the columella, rather more prolific than usual, and combines to form a distinct superficial net of large even meshes. From the outer arcs of the bounding net spring rather long acute processes which should support the peridium. This, however, is altogether rudimentary. In most places there is no sign of peridium at all, but here and there between contiguous sporangia opposite processes unite and at their point of union a tiny circular disk of the peridial membrane appears. At intervals, therefore, over the entire sporangium are seen these small brown disks, each about equalling in diameter the size of the average mesh. At other points the sporangia do not seem at all coalescent, but where the opposing processes do meet the union is perfect and the little disk seen edgewise looks like some delicate counter strung upon a wire.

The interest attaching to this in view of what has been said about Amaurochaete and Brefeldia is obvious.

Under the lens the spores and capillitium are concolorous, dark fuscous, the spores distinctly verruculose, about 12.5 µ.

The original gathering here described was from New Jersey; twenty years later Mr. Ellis was so fortunate as to find again fine specimens all on oak bark. The sporangia are quite small, only 3 mm. high, when blown out concolorous with the habitat.

2. Stemonitis trechispora (Berk.) Torr.

Plate XX., Figs. 11, 11 a, 11 b, 11 c.

• 1909. Stemonitis fusca (Roth) Rost. var. trechispora (Berk.), Fl. Myxom., Torrend, p. 141.
• 1911. Stemonitis fusca var. trechispora Torr., List., Mycetozoa, 2nd ed., p. 144.

Fructification in form of aggregations of more or less coalescent, small, dark-brown or dull black, sessile sporangia; hypothallus continuous, well-developed; columella black, gently tapering to a point beneath the apex, the capillitial branches, irregular, few, but passing into an open rather evenly-meshed net, the mesh several times the[Pg 160] spore-diameter, free-ending branch-tips not lacking; the spores by transmitted light distinctly brown, the epispore a beautiful reticulation, a dozen or more cells to the hemisphere, 10–12 µ.

This is entered sometimes as a variety of S. fusca to which species relationship would seem remote. The differences lie in form, color and structure. The spores alone are distinctive; there are none such, so far, none just like them, elsewhere in the genus. Torrend and Lister both enter the form as varietal; why not set it out, and save questions? The habitat approaches that of Amaurochaete, but the sporangia are distinct.

For our specimens we are indebted to the kindness of Dr. Roland Thaxter. The specimens were taken in a half-dry marsh, near Cambridge.

Material from Toronto sent by Professor Faull is also provisionally here referred. The form has netted spores, but they are not quite the same. The structure besides is more that of an amaurochaete; it has the peculiar basal webs and band-like stipes at base, stipes that never rise from horizontal to perpendicular and characterize Reticularia and especially Brefeldia as well as the usual amaurochaete. See Plate XX., Figs. 9, 9a, 9b.

3. Stemonitis fusca (Roth) Rost.

Plate VI., Figs. 4, 4 a, 4 b

• 1787. Stemonitis fusca Roth, Röm. Mag. Bot., I., p. 26.
• 1875. Stemonitis fusca (Roth) Rost., Mon., p. 193.
• 1892. Stemonitis fusca Rost., Massee, Mon., p. 72.
• 1895. Stemonitis fusca Roth, List., Mycetozoa, p. 110.
• 1899. Stemonitis fusca (Roth) Rost., Macbr., N. A. S., p. 115.
• 1899. Stemonitis maxima Schw., Macbr., N. A. S., p. 116.

Sporangia tufted, generally in small clusters 6–8 mm., the individual sporangia slender, cylindric, blue-black or fuscous, becoming pallid as the spores are lost, stipitate; stipe short, about one-fourth the total height, black, shining; hypothallus scanty, but common to all the sporangia; columella prominent, attaining almost the apex of the sporangium, freely branching to support the capillitial net; capillitium of slender dusky threads, which freely anastomose to form a dense interior network, and outwardly at length combine to form a[Pg 161] close-meshed net; spores pale, dusky violet, usually beautifully spinulose-reticulate, but sometimes warted or spinulose only, or nearly smooth, 7–7.5 µ.

As here set out the description is intended to include S. maxima Schw. of the former edition. Rostafinski, Mon. l. c., describes S. fusca Roth. as having "spores smooth." Since most American gatherings have reticulated spores, and since Schweinitz described a black American species, his specific name seemed appropriate for all except smooth-spored forms.

In the meantime two things have happened; Mr. Lister has examined the specimens remaining in the Strasburg herbarium and finds them with reticulate spores. The statement quoted from the Monograph evidently does not apply to all of Rostafinski's material; but under the circumstances the name fusca may easily take the field, especially since another discovery makes for the same conclusion. The evidence is good that S. maxima Schw. was indeed the largest, i. e. perhaps, the tallest stemonitis he ever saw! probably, as his scanty herbarium-remnant shows, S. fenestrata Rex!

4. Stemonitis uvifera n. s.

Plate XX., Figs. 8, 8 a, 8 b, 8 c.

Sporangia tufted, generally in medium-sized clusters much as in S. fusca. The individual sporangium 7–9 mm. high, dark, slender, brown, becoming dull black or pallid as the spores are lost, stipitate, the stipe about one-fourth to one-third the total height, black polished shining; hypothallus distinct, common to all sporangia, purple-brown, shining; columella distinct, attaining almost the summit of the sporangium but inclined to waver a little at last, in other words, flexuose toward the top, freely branching, the branches rather stout, anastomosing to support the capillitial net; the meshes larger, several times the spore-diameter, the spores sooty-brown, distinctly warted or spinulescent, about 7–8 µ, clustered in groups of four or more.

Mt. Rainier, Washington,—1914.

5. Stemonitis dictyospora Rost.

• 1873. Stemonitis dictyospora Rost., Mon., p. 195; Myc. Fen., pp. 114, 122.
• 1879. Stemonitis dictyospora Rost., Mass., Mon., p. 83(?).[Pg 162]
• 1888. Stemonitis dictyospora Rost., Sacc. Syl. Fung., Vol. VII., p. 397.
• 1893. Stemonitis castillensis Macbr., Nat. Hist. Bull., Vol. 11, p. 381. Plate X., Figs. 5, 5 a, 5 b.

Sporangia crowded in colonies of unusual size, 4–8 cm., tall, rigid 18–25 mm., slender, erect, stipitate, black throughout; the columella prominent, reaching nearly to the apex, abundantly branched, the branches forming an intricate dark brown capillitium; the net large-meshed several times the spore-diameter; the spores reticulate, spinulose, clear violet, 7–8 µ.

We here recover as is believed one of Rostafinski's best-described species. Our material is from Nicaragua, by kindness of Professor Shimek. Its relationship is with S. fusca where Rostafinski placed it. The phrase describing spore-color is his.

6. Stemonitis nigrescens Rex.

• 1891. Stemonitis nigrescens Rex, Proc. Phil. Acad., p. 392.
• 1911. Stemonitis fusca Roth, Lister, Mycetozoa, 2nd ed., p. 143.

Sporangia gregarious, upon a common hypothallus, erect, small, cylindric, stipitate; stipe black, extremely short, about half a millimetre; columella reaching the apex; capillitium violet-black, darker near the surface, forming a complete superficial net at the lower part of the sporangium only, elsewhere irregular or vanishing; spore-mass nearly black; single spores violet-black under the lens, the epispore spinulose and reticulate, about 8 µ.

The author of this species remarks: "This species is noteworthy for its comparatively short stipes, its very spinulose spores, and its black or nearly black color, the slight violet tint being only apparent on close inspection, especially in fresh moist specimens."

It is a small but very beautiful form, at first sight to be mistaken for a short S. fusca, though much more intensely black. The capillitium is concolorous, the inner network of rather few open meshes, the outer of large hexagonal openings, the arcuate threads of which are remarkable for the size, and especially the number, of the peridial processes, as many as five or six sometimes appearing along one side of a single mesh. The stipe is very short, and the columella runs as a straight, gradually diminishing axis to the very apex of the sporangium. Total height 3–5 mm.[Pg 163]

The English Monograph includes this with S. fusca; but it seems quite distinct in size, habit, color, etc., and has been found in the mountainous regions of Virginia and North Carolina, as well as about Philadelphia.

7. Stemonitis virginiensis Rex.

• 1891. Stemonitis virginiensis Rex, Proc. Phil. Acad., p. 391.
• 1899. Stemonitis virginiensis Rex, Macbr., N. A. S., p. 130.
• 1911. Comatricha typhoides Rost., List., Mycetozoa, 2nd ed., p. 158.

Sporangia erect, gregarious, from a common hypothallus, generally clustered, cylindric or elongate-ovate, stipitate; stipe black, shining; columella reaching the apex, where it blends with the capillitium; capillitium delicate, the meshes of the net small, scarcely greater than the diameter of the spores; spore-mass umber brown; epispores reticulated, with ten or twelve meshes to the hemisphere, 5–7 µ.

This is a beautiful, and, as it seems to us, a very distinct, species. The markings on the epispore are sufficient to identify it. These are conspicuously banded somewhat as the spores of Trichia favoginea, for example. In habit, size of the sporangia, and capillitial branching, this species recalls Comatricha typhoides (Bull.) Rost. All the sporangia examined are, however, plainly stemonitis in type, possessing the characteristic superficial net.

Until further light this may stand as offered in the first edition. Miss Lister prefers to enter it, banded spores and all, with the comatrichas, on account of color, size and occasional default (?) of surface net.

Virginia, Dr. Rex.

8. Stemonitis webberi Rex.

Plate XI., Figs. 6, 7, 8.

• 1891. Stemonitis webberi Rex, Proc. Phil. Acad., p. 390.

Sporangia clustered, usually in small tufts 1 cm. wide, rusty brown in color, 8–10 mm., including the stipe, which is jet black, shining, and much expanded at the base; hypothallus continuous, well-developed, a thin, transparent pellicle; columella black, tapering upward, giving off at intervals the capillitial branches, and becoming dissipated[Pg 164] just below the obtuse apex; inner capillitial network very open, the branches far apart, anastomosing but a few times before breaking into the surface net to form large, irregular meshes, 50–125 µ; spores minutely roughened, fuscous, 8–9 µ.

These three forms, 8, 9, 10, are sometimes entered as varieties of a single species. Dr. Rex himself was inclined to take that view. There is no doubt of close similarity; it is a question of clearness in our dealing with the subject.

All three forms occur abundantly in the Mississippi Valley, but are generally,—always, as it seems to the writer,—distinguishable by the hand-lens. If we take No. 9 as type, 10 has an eccentric columella; 8 is shorter, about 1 cm., of a different tint, Dr. Rex even says "spores ferruginous in mass". To the west and southwest, the capillitium becomes coarser, more decidedly brown. In short, however similar in presentation the phases may sometimes appear, it would seem that each at its best is distinct enough for immediate recognition.

West of the Mississippi River chiefly: Iowa, South Dakota, Nebraska, Kansas, Oklahoma, New Mexico, etc.

9. Stemonitis splendens Rost.

Plate VI., Figs. 6, 6 a, 6 c, 7, 7 a.

• 1875. Stemonitis splendens Rost., Mon., p. 195.
• 1880. Stemonitis morgani Peck, Bot. Gaz., V., p. 33.
• 1893. Stemonitis splendens Rost., Macbr., Bull. Lab. Nat. Hist., Vol. II, p. 381.
• 1894. Stemonitis splendens Rost., List., Mycetozoa, p. 112, in part.
• 1899. Stemonitis morgani Peck, Macbr., N. A. S., p. 118.
• 1911. Stemonitis splendens Rost., List., Mycetozoa, 2nd ed., p. 145.

Sporangia clustered irregularly, sometimes forming patches 6–10 centimetres or more in extent, rich purple-brown in mass, cylindric, long, 15–18 mm., stipitate; stipe black, polished, shining, rising from a common hypothallus, which extends as a thin silvery film beneath the entire colony, but does not usually transcend its limits; columella black, percurrent, sparingly branched; capillitium of fuscous threads, within forming a network very open, the branches scarcely anastomosing until they reach the surface where they form the usual net of[Pg 165] small meshes, pretty uniform in size, and presenting very few small, inconspicuous peridial processes; spores brown, very minutely warted, about 8 µ.

This elegant species occurs not rarely on rotten wood, usually in protected situations, although sometimes on the exposed surfaces of its habitat. The sporangia attain with us unusual height, sometimes 2 cm.; plasmodia, 6–8 cm., in diameter. The clear brown tufts appear in the autumn, marvels of graceful elegance and beauty; at sight easily recognizable by the large size and rich color. In Iowa it is almost universally present on fallen stems of Acer saccharinum Linn., and it appears to be widely distributed, by far the most beautiful of all this beautiful series.

New England to Iowa, South Dakota, Washington, and British Columbia. Professor Shimek brings a dusky phase from Nicaragua!—the type?

The plasmodium is white on maple stems, more creamy on stems of linden, on which wood it is more rarely found: occasionally on ash-stumps; even on the fallen bark of trees preferred.

In 1875 in his famous Monograph, Rostafinski set out three species with "dusky violet spores". These are his Nos. 94, 95 and 96.

The first one of these he calls S. fusca, "spore-mass, etc., violet-black, individual spore clear violet, smooth, 7–9 u."

The second species he writes down S. dictyospora, "hypothallus, stalk, columella, capillitium and spore-mass, violet-black, spore netted and fringed, clear-violet, 7–9 µ."

The third species is S. splendens, "hypothallus stalk, columella and spore-mass violet-black, spore smooth, clear-violet, 7–8 µ."

It will be observed that in color down to color of the spore by transmitted light, the three species are exactly the same; constitute a suite, so to say. It has since turned out, as noted under our No. 3, that the spores of S. fusca are netted. Error in description here is not surprising; the reticulations are sometimes faint. In S. dictyospora they are admittedly strong, and the inference was that the 'gladkie' spores of the third species might be netted also. This is no criticism: lenses were fifty years since not nearly so good for such discoveries as the oil-immersion is now.[Pg 166]

However; Rostafinski made his specific diagnosis turn largely upon the mesh-width in the superficial net. This comes out in the 'opis' following the description, and upon this the European decision in Rostafinski's favor as against S. morgani largely turns. Tropical gatherings are probably always darker, and evidently from such, from the north coast of South America, the original description was drawn. Specimens before us from the same latitude are dusky indeed; no clear brown at all, but purplish withal.

For the sake of harmony we may therefore now substitute the earlier name "with reservations"! but our description remains as before, presenting the really splendid, shining things that adorn our northern fields. Dr. Rostafinski called the large open meshes of the net 'oka', eyes; lumina let us say! quite uniform they are in 9 and 10, much less so in 8.

10. Stemonitis fenestrata Rex.

• 1890. Stemonitis splendens R. f. fenestrata Rex, Proc. Phil. Acad., p. 36.

Sporangia aggregated, in tufts 2 cm. or more in diameter, rich purple brown, on a common hypothallus, more or less erect, stipitate, tall, about 2 cm., slender, triangular in section; stipe black, about one-third the total height, passing into a slender columella which is lateral in position, not central, but little branched, continued almost to the apex; the capillitium consisting almost entirely of the peripheral net, which presents meshes of unusual uniformity of size and shape; spores in mass brown, colorless by transmitted light, nearly smooth, 6–7.5 µ.

The remarkable shape of the sporangium and the peculiar regularity of the surface net, the lateral columella, all combine here to warrant the erection of a distinct species. Dr. Rex referred this to S. bäuerlinii Mass. At that time he had not the author's description, and had seen only a very poor fragment received with notes in a letter. Mr. Massee's description makes it immediately evident that whatever other affiliations S. bäuerlinii may have, by description it has at least none with S. fenestrata nor with our northern form of S. splendens. Massee's species is described as having the "mass of spores black", the capillitium with "branches springing from the columella;[Pg 167] the main branches more and more numerous, thicker and irregular towards the apex of the sporangium, and often form irregular flattened expansions":—etc. This suggests some form of S. dictyospora Rost.: see under our No. 5. Possibly for such reasons Lister referred it to S. splendens Rost., which as we have just seen, was undoubtedly regarded by the author as a form of the fuscous group.

The long, slender, simple columella is not only lateral, but occupies indeed the sharp vertical angle of the triangular, prismatic sporangium. Furthermore, the sporangium is at maturity strangely twisted, so that the columella in its ascent accomplishes one or more spiral turns. In forms collected by Dr. Rex, which seemed to him most nearly to agree with Massee's species, the inner capillitium is somewhat abundant, but the character of the columella just the same.

Pennsylvania, Ohio, Kansas, Colorado, Iowa; India!

11. Stemonitis smithii Macbr.

• 1893. Stemonitis smithii Macbr., Bull. Lab. Nat. Hist. Ia., II., p. 381.
• 1894. Stemonitis microspora List., Morg., Jour. Cin. Soc., p. 54.
• 1911. Stemonitis ferruginea var. smithii Lister, Mycetozoa, 2nd ed., p. 150.

Sporangia in small clusters, close-packed and erect, not spreading, bright ferruginous prior to spore dispersal, cylindric, stipitate, of varying height; stipe jet-black, shining, about one-third the total height; hypothallus generally well developed; columella black, gradually tapering, at length dissolving in capillitial threads and net some distance below the diminished plumose apex; capillitium of fuscous threads, the inner network of abundant, sparingly united branches uniformly thickened, the surface net very delicate, composed of small, regular, polygonal meshes, the peridial processes few; spore-mass bright ferruginous, spores by transmitted light pale, almost colorless, smooth, 4–5 µ.

The species as thus constituted includes forms varying in size from 2.5–3 mm. only. The common form heretofore known everywhere in America as S. ferruginea is from 10–15 mm. high. The type to which the specific name S. smithii was originally applied is 2.5 mm. high and rejoices in smooth, almost colorless spores, 4–5 µ.

The plasmodium in the case of the species now considered is as[Pg 168] concerns the type, of course, unknown. In one or two gatherings referred here the color of the plasmodium was noted greenish-yellow. This has the look of S. flavogenita; but small spores and delicate make-up take it the other way. Miss Lister makes it varietal to No. 12, next following.

12. Stemonitis axifera (Bull.) Macbr.

Plate VI., 5, 5 a, and 5 b.

• 1791. Trichia axifera ferruginea Bull., Champ. de la Fr., p. 118, tab. 477.
• 1818. Stemonitis ferruginea Ehr., Syl. Myc. Berol., p. 20; et auct. Europ. ex parte; Americ., non.
• 1894. Stemonitis ferruginea Ehr., List., Mycetozoa, p. 115, in part.
• 1899. Stemonitis axifera (Bull.) Macbr., N. A. S., p. 120, in part.
• 1911. Stemonitis ferruginea Ehr., Lister, Mycetozoa, 2nd ed.

Sporangia terete, acuminate, fasciculate small in dense clusters, distinctly ferruginous in color, stipitate, from 10–15 mm. in height; the stipe black one-third to one-half the total height, not shining or polished; columella evenly branching, dissipated before reaching the acuminate apex; capillitium-branches clear brown anastomosing and dividing more or less to bear the superficial fine-meshed net; spores pallid, faintly ferruginous, smooth or nearly so, 5–6 µ.

This would seem to be the common ferruginous species of the world. Doubtless Micheli had the thing before him when he drew Tab. 94, clathroidastrum, Hoffman and Jacquin seem to have recognized the form. To be sure, under the present plasmodic limitations we cannot be quite certain about these references. Not until 1791 does anyone write down a particular species as marked by a white plasmodium, and distinguish it from other similar fructifications having similar origin. Bulliard, l. c., does this, discriminating between T. axifera ferruginea and C. typhoides; see under the last-named species. Youthful Ehrenberg, in his doctor's thesis, nearly thirty years later, draws a similar parallel but ignores the great French author, writing S. ferruginea Ehr. as though the thing had never been seen before! By this name it has been called until very lately; Fries accepting it, but noting that the plasmodium, for him at least, was yellow!

In 1904 Dr. E. Jahn, following Fries' suggestion, established the fact that Ehrenberg's white-plasmodic species had small spores, that[Pg 169] Fries had in mind a form with larger spores, having indeed yellow plasmodium; but see number 13 below.

It is for the present assumed that the plasmodium of our American S. axifera is white. So far, there are few or no observations which establish the fact. The color, the small smooth spores, the fine-meshed capillitial net and the general dimensions determine the reference.

13. Stemonitis flavogenita Jahn.

Plate XX., Figs. 10, 10 a, 10 b.

• 1829. Stemonitis ferruginea Ehr., Fries, Myc. III., p. 158, Syn. excl.
• 1899. Stemonitis axifera (Bull.) Macbr., N. A. S., p. 120, in part.
• 1904. Stemonitis flavogenita Jahn, Abh. Bot. Ver. Brandenb., XLV, p. 265.
• 1911. Stemonitis flavogenita Jahn, List., Mycetozoa, 2nd ed., p. 149.

Sporangia cylindric, obtuse, closely fasciculate, "cinnamon brown," stipitate, 5–7 µ; stipe short, black, columella ceasing abruptly below the apex; capillitium a loose net-work with many broad expansions; the peridial net very delicate, the meshes small but uneven, 6–15 µ, with many projecting points; spores pale ferruginous, verruculose, 7–9 µ.

This is S. ferruginea Ehr. of Fries with its plasmodium yellow. Fries says "flavicat," becomes yellow, if one may follow the analogy of corresponding Latin verbs of color, so that the record of color-changes in the present species is yet to be recorded.

Until further experience may advise to the contrary, we may assume that all stemonites cinnamon-brown in color, with widened columella-tip, and pale yellowish spores 7–9 µ in diameter, have at some time in their history a yellow plasmodium, and accordingly represent in America the new-found species.

The larger spores, and, the strange proliferate development of the columella-tip, to which Miss Lister has happily called attention, constitute the essential diagnostic features here.

Our only specimens so far are from Oregon.

14. Stemonitis pallida Wingate.

Plate XIII., Fig. 3

• 1897. Stemonitis pallida Wing., N. A. F., Ell. and Ev., No. 3498.
• 1899. Stemonitis pallida Wing., Macbr., N. A. S., p. 123.
• 1911. Stemonitis pallida Wing., List., Mycetozoa, 2nd ed., p. 149.

[Pg 170]

Sporangia gregarious, or somewhat clustered, erect, cylindric obtuse, short, blackish brown, rubescent, becoming pallid, stipitate; stipe short, black, polished, rising from a thin, brown, or iridescent hypothallus; columella percurrent, ceasing abruptly at the apex; capillitium filling the interior with abundant branches which form at the surface a close-meshed net, little developed above, making the apex very blunt; spores in mass, dark brown, by transmitted light dusky, nearly smooth, 7.5 µ.

This species is well recognized at sight, among the fuscous forms, by its scattered, erect habit. In color it is not unlike S. fusca, but has an added reddish tinge. In form it is peculiar by virtue of the blunt rounded apex which seems to be a constant character. The spores under moderate lens are perfectly smooth, under the 1–12 they present very delicate low scattered papillæ.

Rare; eastern part of United States.

15. Stemonitis carolinensis Macbr.

Plate XIII., Fig. 5.

• 1894. Stemonitis tenerrima Berk. & C., Morg., Jour. Cin. Soc., p. 53.
• 1899. Stemonitis carolinensis Macbr., nom. nov., N. A. S., p. 152.
• 1911. Stemonitis pallida Wing., Lister, Mycetozoa, 2nd ed., p. 149.

Sporangia tufted in scattered clusters, small, slender, cylindric but tapering from the apex, at first ferruginous then ashen or purplish, stipitate; the stipe short, black and shining, one-fourth the total height or less, even; hypothallus well developed, black or very dark brown; columella black, gradually diminishing, at length dissipated some distance below the clavate or acuminate apex of the sporangium; capillitium dense, the inner of many, scarcely expanded, pallid, freely anastomosing branches, the outer a net of very small meshes, often less than the spores, 3–15 µ, peridial processes imperceptible; spore-mass pale ferruginous, spores by transmitted light pale violaceous brown, smooth, 6–7 µ.

Very closely related to the preceding, but recognizable by its proportionately much more slender, taller, acuminate sporangia, paler, and denser capillitium and the remarkably close-meshed net.

Not uncommon south: Kentucky, Alabama.[Pg 171]

16. Stemonitis herbatica Pk.

Plate XVI., Figs. 14, 14 a, 14 b

• 1874. Stemonitis herbatica Peck, Rep. N. Y. Mus., XXVI., p. 75.
• 1899. Stemonitis axifera (Bull.) Macbr., N. A. S., p. 120, in part.
• 1911. Stemonitis herbatica Pk., Lister, Mycetozoa, p. 148.

Sporangia clustered, in scattered tufts, cylindric, obtuse, pallid ferruginous, stipitate or sometimes nearly sessile; stipe fuscous or jet-black, only slightly expanded below, much shorter than the columella; hypothallus scanty or none; columella lessening upward, sometimes attaining the apex of the sporangium, sometimes dissolved in capillitial threads some distance below; capillitium of rich brown threads forming the usual inner network of medium density, with many wide expanded nodes, the surface net made up of delicate, almost colorless threads surrounding small polygonal meshes; spore-mass ferruginous, spores by transmitted light very pale, brownish, minutely warted, 7–9 µ.

The plasmodium of this species is variously cited from white to yellow. Probably each report is true, dependent on the relative time of the observation.

The low tufts of brown sporangia with short black stipes, borne often as Dr. Peck found them, assembled on living leaves, distinguish this little species. In the former edition this form was tentatively enrolled under S. axifera (Bull.); but see further under that species.

Probably widely distributed, but confused with short forms of other species; sometimes also on rotten wood or other substratum; so reported.

New York to Iowa; Washington and Oregon. Reported also from Europe.

3. Comatricha (Preuss) Rost.

• 1851. Comatricha Preuss, Linnaea, XXIV., p. 140.
• 1873. Comatricha Rostafinski, Versuch, p. 7.

Sporangia cylindric or globose, stipitate; stipe prolonged upward to form a more or less extended and tapering columella bearing branches on every side, which by repeated divisions and reunions form the capillitium; ultimate branch-tips free, not supporting a surface[Pg 172] net parallel to the peridial wall; peridium evanescent, perhaps sometimes not developed at all.

The genus Comatricha was set off from Stemonitis by the joint effort of Preuss (1851) and Rostafinski (1873–5). Preuss included in his genus, Comatricha, alien forms, and besides failed to give an accurate definition; included, however, in his list some species which have since been known by his generic name.

The distinction between the two genera is almost an artificial one, and species are sometimes arbitrarily assigned to one genus or the other. The diagnosis in any case turns upon the presence or absence of a surface net, formed, in Stemonitis, by the anastomosing of the ultimate divisions of the capillitial branches. In Comatricha the anastomosing is general, from the columella out, and is not specialized at the surface.

Recent attempts to reunite the genera here compared seem to result in no apparent advantage. The genera come very near together, but their separation along the line suggested by Rostafinski remains convenient.

Key to the Species of Comatricha

1. Comatricha cæspitosa Sturgis.

Plate XI., Figs. 12, 13, 14.

• 1893. Comatricha caespitosa Sturg., Bot. Gaz., XVIII., p. 186.
• 1894. Diachaea thomasii Rex, var., List., Mycetozoa, p. 92.
• 1899. Comatricha caespitosa Sturg., Macbr., N. A. S., p. 124.
• 1911. Diachaea caespitosa Lister, Mycetozoa, 2nd ed., p. 121.

Sporangia densely crowded or cespitose, sub-sessile or short stipitate, clavate, 1–1.5 mm. high, the peridium gray, iridescent with blue tints, comparatively permanent but finally disappearing; columella attaining two-thirds to three-fourths the height of the sporangium, giving rise throughout its length to the dense blackish capillitium; hypothallus delicate, inconspicuous; capillitium, the main branches thick at the point of origin, frequently anastomosing, and becoming gradually thinner toward the surface of the sporangium, the tips pointed, free, forming the network; spores blackish-violet in mass, by transmitted light pale brownish-violet, rough, 9.5–13 µ.

A very distinct and curious species. The sporangia are densely crowded, though by the nature of habitat somewhat tufted. The shape of the individual sporangium is quite uniformly clavate or obovate, decidedly truncate above. The spores are uniformly verruculose and plainly unequal.

This species, as indicated, was by its author described as a comatricha. To transfer it to another genus seems idle, especially when long established generic boundaries must be seriously disturbed expressly to admit the new arrival.

New England, North Carolina, on moss and lichens.—Dr. Sturgis.

2. Comatricha cylindrica (Bilgram) Macbr.

• 1905. Diachaea cylindrica Bilgram, Proc. Acad. Nat. Sci. Philad., 524.
• 1911. Diachaea cylindrica Bilgram, List., Mycetozoa, 2nd ed., p. 121.

Sporangia cylindrical with obtuse apex, sessile, gregarious, iridescent,[Pg 174] steel-gray or bronze, 1 to 1.7 mm. high, .5 to .65 mm. thick; hypothallus whitish, rugose; sporangium-wall membranous, hyaline, not adhering to the capillitium; columella arising from the hypothallus and extending nearly to the apex, brown, very light and semi-translucent near the base, irregular, flexuous, limeless throughout; capillitium brown, radiating from the columella to the periphery, repeatedly branching and anastomosing; spores warted, the warts connected by ridges forming a more or less perfect, coarse reticulation, violaceous, pale, 10–12 µ.

This is a very interesting species closely related to the preceding from which it differs chiefly in the reticulation and generally more uniform character of the spores. The author hesitated about the generic reference, finally referring it to Diachaea despite the lack of calcium, because it was sessile and had a peridium rather more persistent than is usual in comatrichas. But the presence of lime in stipe and columella is an essential element in the diagnosis of Diachaea, while length of stem is everywhere variable in stipitate forms of every genus, and the persistence of the peridium is also an uncertain factor; hangs on long in C. typhoides, e. g.

On dead twigs, etc.—Philadelphia,—Mr. Bilgram; New Hampshire.

3. Comatricha flaccida List.

• 1894. Comatricha flaccida List., Morg., Jour. Cin. Soc., p. 51.
• 1894. Stemonitis splendens, var. flaccida List., Mycetozoa, p. 112.
• 1894. Comatricha flaccida (List.) Morg., Macbr., N. A. S., p. 133.
• 1911. Stemonitis splendens, var. flaccida List., Mycetozoa, 2nd ed., p. 146.

Sporangia semi-erect, close crowded in tufts two inches in diameter, ferruginous, from a dark brown hypothallus, sessile or short stipitate; columella weak, crooked, percurrent, generally enlarged irregularly at the apex; capillitium of few, slender, brown branches which anastomose sparsely and irregularly as in C. irregularis, and present when freed from spores the same chenille-like appearance; spore-mass ferruginous brown; spores by transmitted light bright reddish brown, minutely warted, 8–10 µ.

"Growing on old wood and bark of Oak, Willow, etc. The component[Pg 175] sporangia 5–10 mm. in length. The early appearance is much like that of a species of Stemonitis, but the mature stage is a great mass of spores with scanty capillitium, as in Reticularia; the columellas, however, are genuine and not adjacent portions of wall grown together."—Professor Morgan.

Professor Morgan's herbarium material is at hand for study. It meets his description, needless to say, very generally. In what remains of the type the membranous connections are obscure; in fact the relation of such peridial (?) fragments to the capillitium in any way, is no longer evident. But in any event the colony does not impress one as something prematurely or improperly developed, a stemonitis gone begging;—nothing of that kind; it is clearly a comatricha, easily identifiable with no trace of a surface net but, with long free tips in plenty.

Misled no doubt, by the peridial fragments referred to, Mr. Lister in Mycetozoa, l. c., associated this with S. confluens Cke. & Ell., but entered it as a variety of S. splendens Rost., just the same. In the second edition of the Monograph, Ellis' species is set out, but Morgan's retains the old position.

In light of present knowledge, the relationship suggested would be difficult of proof. If C. flaccida Morgan be related to the splendens group at all, it must be with the form known as S. webberi Rex., but it differs from this in almost every particular. It has no net, with meshes uniform or diverse; it is clear brown in color, with a tinge of red, beneath the lens; the spores are smaller, distinctly warted and with the reddish tinge of the capillitium; and in short, it seems to be a comatricha and not a stemonitis.

Specimens from western Washington differ in some particulars but are apparently the same thing.

Ohio, Kentucky, Washington, California; not common.

4. Comatricha longa Peck.

Plate VI., Figs. 2, 2 a, 2 b.

• 1890. Comatricha longa Peck, Rep. N. Y. Mus., XLIII., p. 24.

Sporangia crowded in depressed masses or tufts, black, long, cylindric, even, stipitate; stipe black, shining, generally very short; hypothallus[Pg 176] well developed, black; columella black, slender, weak, generally dissipated some distance below the apex; capillitium of slender brown or dusky threads anastomosing to form an open network next the columella, but extended outwardly in form of long free slender branchlets, now and then dichotomously forked; spore-mass blue-black, spores by transmitted light dark brown, globose, spinulose, some of them faintly reticulate, about 9 µ.

A very remarkable species. Rare in the west, more common, as it appears, in the eastern states. The sporangia occur in tufts about 1 or 2 cm. wide, springing generally from crevices in the bark of decaying logs, especially willow and elm, in swampy places. The sporangia are remarkable for their great length. Generally about 20–25 mm., specimens occasionally reach 50 mm.! The capillitial branches are so remote that the spores are scarcely retained by the capillitium at all. Well described and figured by the author of the species, Forty-third Rep. N. Y. State Museum, p. 24, Pl. 3.

New York, Pennsylvania, Ohio, Iowa.

5. Comatricha irregularis Rex.

• 1891. Comatricha irregularis Rex, Proc. Phil. Acad., p. 393.

Sporangia crowded in flocculent tufts, very dark brown or black, semi-erect or drooping, 4–5 mm. in height, irregularly cylindric, variable, stipitate; stipe black, distinct, often one-half the total height; hypothallus well developed, brown, shining; columella central, slender, flexuous, reaching the apex, where it blends, by branching, with the capillitium; capillitium loose, open, composed of arcuate threads which radiate from the columella, and are joined together, forming a central, irregular reticulation of large meshes, brown, paler toward the surface, where the free ends are sometimes colorless; spore-mass black, spores by transmitted light brown, minutely warted, 7–8 µ.

Related, no doubt, to C. longa, but differing in habit, stature, as in texture and structure of the capillitium. In C. longa the inner net is extremely simple,—a row or two of meshes at most, and the radiating branches are long and straight; in the species before us the inner network is well developed, and the radiating branches proportionately shorter and abundantly branching, with pale or white free tips.[Pg 177]

Generally, though not always, found growing in the crevices of the bark on fallen logs of various deciduous trees. September. Not common.

This is thought to be C. crypta Schw., N. A. F., 2351; but the description under that number does not make clear what form Schweinitz had before him, the present species or C. longa, and the herbarium specimen of Schweinitz is "utterly lost"; the later specific name is accordingly adopted.

New England west to the Cascade Mountains; south to Kansas and Texas.

6. Comatricha laxa Rostafinski.

Plate V., Figs. 5, 5 a.

• 1875. Comatricha laxa Rost., Mon., p. 201.
• 1877. Lamproderma ellisiana Cooke, Myx. U. S., p. 397.
• 1891. Comatricha ellisiana (Cooke) Ell. & Ev., N. A. F., 2696.

Sporangia scattered, gregarious, sub-globose or short cylindric, and obtuse, dusky stipitate; stipe short, black, tapering rapidly upward from an expanded base; hypothallus scant or none; columella erect, rigid, sometimes reaching nearly to the apex of the sporangium, sometimes dichotomously branched a little below the summit, before blending into the common capillitium; capillitium lax, of slender, horizontal branches, anastomosing at infrequent intervals and ending in short, free tips; spores pallid, nearly smooth, 7–9.5 µ.

A very minute, delicate little species, about 1½ mm. high; the stipe half the total height. In general appearance the shorter forms of the species resemble slightly C. nigra, but are distinguished by a much shorter stipe and much more open capillitium. The sporangia of C. nigra mounted on long capillary stipes always droops more or less; the sporangia of the present species stand rigidly erect. The sporangia vary in form and in the branching of the columella. In the more globose phases, the columella almost always shows a peculiar dichotomy near the apex; in the cylindric types, this peculiar division fails.[36] In fact, the shape is determined chiefly by the mode of branching as affects the columella. Rostafinski's figure, on Tab. XIII, does[Pg 178] not present the type usually seen in this country, nor even in Europe if we may judge from later illustrations.

The species with us has received various names, but so far as can be determined, all apply to the same thing, and comparison of specimens from Mr. Ellis with those from Europe show the correctness of the nomenclature here adopted.

Rare, but widely distributed; across the continent.

7. Stemonitis suksdorfii Ell. & Everh.

Plate XI., Figs. 9, 10, 11.

• 1882. Stemonitis suksdorfii Ell. & Everh., Bull. Washb. Coll., Vol. I., p. 5.
• 1892. Stemonitis suksdorfii Ell. & Everh., Mass., Mon., p. 76.

Sporangia scattered in small tufts or gregarious, cylindric, obtuse at both ends, sometimes widened above, black, 2–6 mm., stipitate; stipe jet-black, shining, even, about one-half the total height; hypothallus not continuous, dark brown; columella black, rather slender, terminating in two or more large branches just below the apex; capillitium exceedingly dense, dark fuscous or black, the flexuous threads anastomosing in a close network, with abundant free pallid extremities; spores in mass, blue-black, by transmitted light fuscous or dark violaceous-brown, minutely warted, 10–12 µ.

Easily recognizable at sight by its sooty color. Entirely unlike any of the preceding. The type of the capillitium is that of C. pulchella,
but it is very much more dense and entirely different in color. The
sporangia are often widened above, and fairly truncate; the total height about 6 mm. Found on the bark of fallen twigs of Abies, Larix, etc. Distributed by Ell. & Everh. under this name as an exsiccata. The evanescent peridium is colorless; when free, white or silvery.

8. Comatricha nigra (Pers.) Schroeter.

Plate XI., Figs. 1, 2, 3.

• 1791. Stemonitis nigra Pers., Gmel., Syst. Nat., p. 1467.
• 1801. Stemonitis ovata, var. nigra Pers., Syn., p. 189.
• 1863. Stemonitis friesiana DeBy., Rab. Eur. Fung., No. 568.
• 1875. Comatricha friesiana (DeBy.) Rost., Mon., p. 200.[Pg 179]
• 1889. Comatricha nigra (Pers.) Schroeter, Pilz. Krypt. Fl. v. Schles., I., p. 118.
• 1894. Comatricha obtusata Fr., Lister, Mycetozoa, p. 117.
• 1899. Comatricha nigra (Pers.) Schroeter, Macbr., N. A. S., p. 128.

Sporangia scattered, ferruginous or dark brown, globose or ovoid, stipitate; stipe long, hair-like, tapering upward, black; hypothallus none; columella rapidly diminished toward the top, at length dissipated; capillitium of slender flexuous threads, radiating horizontally, repeatedly branching and anastomosing to form an intricate dense network, from the surface of which project a few short hook-like peridial processes; spore-mass black, spores by transmitted light dark violaceous, smooth or nearly so, 7–10 µ.

This species, when typical, is easily recognized by its almost globose sporangia mounted on long slender stocks. These are 2 or 3 mm. high and generally persist, as Persoon noticed, a long time after the sporangium has fallen. The sporangia are at first black; after spore disposal pale ferruginous. In shape they vary from ovate to spherical. Sometimes they are umbilicate below, so that a vertical section would be obcordate. Care must be taken to distinguish the present species from blown-out forms of Lamproderma.

This most common species seems to be also the center of widest differentiation. In a valuable paper on the Myxomycetes of Dr. C. H. Peck's Herbarium Dr. Sturgis points out the varying relationships of a group of surrounding forms. According to account C. nigra verges on one side to C. laxa, on the other to aequalis which the Listers enter as varietal here. However, in the former the more rigid, direct and simple branching from the columella is usually determinative; in the latter the color, form, and generally more delicate structure, and a tendency to grow in tufts will serve to distinguish.

In this discussion we have assumed as typical the globose sporangium, with the variations in the direction of ovate, obovate, ellipsoidal, etc., the capillitium flexuous and more richly anastomosing near the columella. On the drier slopes in the mountains of Colorado specimens are especially abundant, in proper season covering apparently the lower surface of every barkless twig or fallen stem or tree entire! In such a field one might imagine every possible variation[Pg 180] open to observation. Probably such is the case; but as a matter of fact a single small plasmodium at lower levels will sometimes show greater range of variation than were noted on the mountain-side. The cylindric forms were for some reason few, and when noted were short, though often surmounting stems of double the usual length.

Rostafinski calls this C. friesiana, a name suggested by De Bary. By this name the species was commonly known for many years. More recently some writers prefer C. obtusata Preuss; but C. obtusata Preuss, as figured by that author (Sturm's Deutsch. Fl., Pl. 70), is surely more likely Enerthenema papillata, and the author says in his description "capillitio vertice soli innato." Persoon certainly recognized the species, and his description, though brief, is yet applicable to no other European species. There seems no reason why the name he gave should not be permanently adopted. Rostafinski's figure, Tab. XIII., shows an ellipsoidal sporangium, not cylindric.

On the lower levels of the Mississippi valley, the species is not common. Possibly overlooked by reason of its minuteness.

Massachusetts, Pennsylvania, Ohio, Iowa, Colorado, North Carolina, Missouri.

9. Comatricha æqualis Peck.

Plate VI., Figs. 3, 3 a, 3 b, 3 c, 3 d; and Plate XVIII., Figs. 13, 13 a, 13 b.

• 1890. Comatricha equalis Peck., Rep. N. Y. Mus., XXXI., p. 42.

Sporangia gregarious, seldom erect, usually inclined, curved or nodding, dark brown, becoming violet, cylindric, acuminate-obtuse, stipitate; stipe about half the total height, 2–2½ mm., black, polished, even; hypothallus well developed, brown, continuous; columella black, tapering gradually, and attaining almost the summit of the sporangium; capillitium dense, of flexuous tawny threads which, by repeated branching, form an intricate network, the free extremities numerous, short, and pale; spores dark violaceous, distinctly warted, 7.5–8 µ.

A very graceful, elegant species, related to C. pulchella and C. persoonii, but distinct by its much greater size and smaller spores. The specimens before show us the perfection of beauty in this genus;[Pg 181] the polished stipe, the symmetrical capillitium, the soft purple-brown tints, are remarkable, and enable one to recognize the form at sight.