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 µ.
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.