23. Physarum murinum Lister.

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 µ.

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.

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 µ.