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 µ., 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 µ. 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.