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._, x.x.x., 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-ma.s.s brown; spores by transmitted light, violet, minutely warted, 7.5-9 .

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 . 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 ma.s.ses 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 .

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-ma.s.s brown; spores by transmitted light, bright lilac, almost smooth, 7-9 .

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._, x.x.xI., 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 ma.s.s, dark red when separated, globose, smooth, 7.5-8.5 .

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 aurantiac.u.m_ 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-ma.s.s black; spores by transmitted light, violet-tinted, 8-10 ., 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 ma.s.s, are, by transmitted light, pale violet, slightly papillose, 8-10, mostly about 8 . 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.