Chapter 8

larger,--to .8 mm. 47. _P. auriscalpium_

xx. Physaroid, base persistent 48. _P. oblatum_

ooo Capillitium nodes pure yellow.

x. Capillitial threads yellow 49. _P. galbeum_

xx. Capillitial threads hyaline 50. _P. tenerum_

xxx. Peridium iridescent.

+ Capillitium persistent 51. _P. flavicomum_

++ Capillitium less persistent, larger 52. _P. bethelii_

SECTION II. TILMADOCHE

I. Aethalioid, gyrose or irregular 53. _P. gyrosum_

II. Fructification stipitate.

1. Sporangia irregular, often convolute, involved 54. _P. polycephalum_

2. Sporangia simple, nutant, discoidal.

_a._ Thin-walled, grey or white. 55. _P. nutans_

_b._ Vari-colored, yellow, greenish, orange, etc. 56. _P. viride_

1. PHYSARUM SERPULA _Morgan._

PLATE IX., Figs. 6, 6_a_, and 6_b_.

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 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 mu. 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.

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 mu.

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 mu.

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 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 6_a_, 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 mu. 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 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 mu.

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 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 mu.

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 densely calcareous, the nodes large, more or less branched, yellow; spores purple brown, closely and minutely warted, 9-14 mu.

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 mu.

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_ 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 3_a_.

1796. _Diderma contextum_ Persoon, _Obs. Myc._, I., p. 89. 1801. _Physarum contextum_ Persoon, _Syn. Meth._, p. 168. 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 mu, 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 mu.

This beautiful species shows a peridium as distinctly double as in 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 mu.

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 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 mu.

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 calcareous, the lime-knots rounded, angular; spore-mass brown, spores clear violaceous-brown, 6-7 mu, 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 mu, 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 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 mu.

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 mu.

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_, 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 mu.

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 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 mu.

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.

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 mu.

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 mu.

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, 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 mu.

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 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 mu.

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, 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 mu. 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 mu. 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 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 mu.

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 mu.

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.

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 mu.

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 mu., almost smooth.

The striking contrast of color between sporangia and stipes renders this species at sight, quite distinct from any related form. The 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 mu. 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 mu.

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.

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 mu.

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 perichaena 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.

28. PHYSARUM NUCLEATUM _Rex._

1891. _Physarum nucleatum_ Rex., _Proc. Phil. Acad._, p. 389.

Sporangia gregarious, spherical, 1/2 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 mu.

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 brown; spores by transmitted light, violet-brown, delicately warted, 7-8 mu.

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, delicate, with more or less well-developed nodules, which are also concolorous; spores by transmitted light, dark brown, thick-walled, rough, nucleated, about 10 mu.

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 mu. _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, 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 mu.

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 LEUCOPHAEUM _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 mu.

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 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 mu.

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. 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 mu.

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 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 mu.

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 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 mu; not infrequently a single spore reaches 16 mu, 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 mu.

The snow-white, nearly smooth stem, the small sporangium (1/2 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.

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 mu.

_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.

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 mu.

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 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 mu.

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.

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 mu 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; capillitial nodes scattered, fusiform, colorless or yellow; spores 16-17 mu." It is evident that whatever Massee may have had in hand as he wrote it was _not P. nicaraguense_, which has spores 10-12 mu 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 mu!" 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 mu.

Northern Europe. (Lusatia) Lausitz, Alb. & Schw.; dim old 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 mu.

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 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 mu.

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.

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 mu. 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 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 _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 mu.

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 mu 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. 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 mu.

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 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 mu.

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.

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 mu.

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; 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 mu.

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 mu.

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.

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 mu.

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.

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 mu.

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 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 mu.

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.

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, Figs. 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., Roemer, _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 mu.

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 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 mu.

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 mu.

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 mu, 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 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 mu.

Reported from Ceylon, Japan, West Indies; Lisbon.

PHYSARUM GULIELMAE _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 mu.

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 mu, marked by strong ridges and spines," 8 mu.

Reported from Antigua.

PHYSARUM AENEUM (_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 mu.

Reported from West Indies, Bolivia.

=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 mu.

In _Mycetozoa, 2nd ed._, the spores are described as "dark or pale purplish brown, spinose, spinulose or nearly smooth, 9-17 mu 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 mu. Spores 17 mu 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.

=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=

A. Dehiscence circumscissile or by the breaking up of the upper wall of the sporangium.

_a._ Sporangia violet or purple 1. _C. paraguayense_

_b._ Sporangia yellow 2. _C. aureum_

_c._ Sporangia white-capped.

1. Sporangia obovoid or globoid 3. _C. leucocephalum_

2. Sporangia cylindric, elongate 4. _C. cylindricum_

B. Dehiscence by a distinct lid.

_a._ Capillitium pale brown 5. _C. concinnum_

_b._ Capillitium white 6. _C. minutum_

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.

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 mu.

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 mu.

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 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 mu.

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 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 mu 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 mu.

This is the common form in the United States. Massee describes it as _C. cylindricum_ Mass., and it seems not to occur in Europe. 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 mu.

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. 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 mu.

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 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 mu.

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:--

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 mu.

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.

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 mu.

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 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. DIDYMIACEAE

=Key to the Genera of the Didymiaceae=

1. Fructification aethalioid 1. _Mucilago_

2. Fructification plasmodiocarpous, or forming more often distinct sporangia.

_a._ Calcareous deposits crystalline, stellate 2. _Didymium_

_b._ Calcareous deposits amorphous, peridium double 3. _Diderma_

_c._ Calcareous deposits in form of scattered scales 4. _Lepidoderma_

_d._ Peridium double, the outer gelatinous 5. _Colloderma_

=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 aethalioid, 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 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, Figs. 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.

Aethalium 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 mu.

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 aethalium 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 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 aethalioid; 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. Lime-crystals merely whitening the peridial wall.

A. Fructification plasmodiocarpous.

_a._ White.

O Capillitium with adherent vesicles 1. _D. complanatum_

OO Capillitium simple 2. _D. anellus_

OOO Capillitium much combined; spores 10-13 mu 3. _D. wilczekii_

OOOO Capillitium crystal-bearing 18_a_. _D. anomalum_

_b._ Yellow or tawny 4. _D. fulvum_

B. Fructification normally of distinct sporangia.

_a._ Sporangia sessile or nearly so; outer calcareous wall conspicuously developed 5. _D. crustaceum_

_b._ Sporangia plainly stipitate.

i. Peridium much depressed; umbilicate below.

O Stipe white 6. _D. squamulosum_

OO Stipe black.

+ Larger, about 7.5-1 mm. 7. _D. melanospermum_

++ Small, about .5 mm. 8. _D. minus_

+++ Sporangia discoid 9. _D. clavus_

ii. Peridium small, globose.

O Stipe dark brown or black; columella dark, obsolete or none. 10. _D. nigripes_

OO Stipe generally paler, of various tints of brown, orange, etc.

+ Columella pale or white, nearly smooth 11. _D. xanthopus_

++ Columella, yellow, discoid, rough 12. _D. eximium_