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

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.

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 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.

THE NORTH AMERICAN
SLIME-MOULDS

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.

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.

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 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.
• 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]

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.

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.

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 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.

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 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, 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.

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.

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.

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.