Chapter VI: Section II: Tilmadoche (1)

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.