The North American Slime-Moulds Part 18

Sporangia scattered, erect, stipitate, generally ellipsoidal, pyriform, rarely globose; peridium membranaceous semi-transparent, studded spa.r.s.ely 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, ac.u.minate; capillitium dense, persistent, the nodes frequently calcareous, rounded, yellow; spore-ma.s.s brown, spores nearly smooth, brownish, 6-7 .

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-ALb.u.m _Lister_

1904. _Physarum luteo-alb.u.m_ List., _Jour. Bot._, XLII., p. 130.

1911. _Physarum luteo-alb.u.m_ 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 .

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-alb.u.m_. 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, 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 ma.s.s of lime forming a s.h.i.+ning ball, not part of the stipe although sometimes produced toward it; spore-ma.s.s black; spores brown-violet, delicately spinulose, 6-7 .

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 spa.r.s.e or absent entirely, in which case the wall has a silvery or coppery metallic l.u.s.tre.

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-ma.s.s or nucleus, and with ordinary nodules small and few, fusiform; spore-ma.s.s brown; spores by transmitted light, violet-brown, delicately warted, 7-8 .

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 l.u.s.tre 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 .

A very handsome little species collected by Professor G. W. Newton in Colorado, at an alt.i.tude 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-ma.s.s brown; spores by transmitted light, pale brown, slightly but plainly warted, about 10 . _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, Ma.s.sachusetts, Pennsylvania. Reported common in Europe, Ceylon, j.a.pan, 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 .

This little species reaches us from California. It appears in late winter in undisturbed gra.s.s 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-ma.s.s black, spores violaceous, minutely roughened, about 8-10 .

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 coa.r.s.er forms called by Rostafinski _P.