This curious but elegant little species is represented by a single colony collected by Professor Morton Peck in Iowa. It resembles D. sauteri but is distinguished by the plicate white wall, the stout columella with its lateral extensions, as by the more delicate spores. On rotten wood.
13. Diderma ochraceum Hoffm.
- 1795. Diderma ochraceum Hoffm., Deutsch. Fl. Tab. 9, 2, b.
- 1911. Diderma ochraceum Hoffm., List., Mycetozoa, 2nd ed., p. 109.
Sporangia gregarious or clustered, .7–1 mm., sessile, globose or sometimes plasmodiocarpous, ochraceous yellow; outer wall cartilaginous with yellow deposits of lime, the inner also yellow, adherent or free; columella not distinct; capillitium simple or branching, purple-brown, hyaline at base; spores spinulose, purplish-grey, 9–11 µ.
Mr. Lister reports this species from Massachusetts.
14. Diderma roanense (Rex) Macbr.
- 1893. Chondrioderma roanense Rex, Proc. Phil. Acad., p. 368.
Sporangia scattered, discoidal, thin, flattened or slightly convex above, plane or plano-concave below, umber-brown, stipitate, the outer peridium smooth, brittle, rupturing irregularly, the basal fragments somewhat persistent, concrete with the inner peridium, which is pure white, except near the columella, and punctate; stipe short, variable, longitudinally ridged, jet-black; hypothallus none; columella flat, discoidal, pale ochraceous; capillitium sparse, white or colorless, composed of simple, rarely forked, sinuous threads occasionally joined by lateral branches; spores dark violaceous, distinctly warted, 12–14 µ.
This species is readily distinguished by its color. The sporangia, found on rotten wood, are large, 1 mm., brown, and have thick, persistent walls. Dr. Rex considered that the species differs from other related forms not only in color, but in the well-marked discoidal columella and the jet-black irregular stipe. It is perhaps most nearly related to the following species.
Tennessee.