Bean—The Myxomycetes of Wisconsin. 1251 
that D. globosum is rare in this country, and that almost every¬ 
thing distributed in he United States as D. globosum belongs in 
D. crustaceum. Lister’s description does not apply as closely 
to this species as does Macbride’s description of B. crustaceum. 
Under the name Ghondrioderma crustaceum Berl., Massee calls 
this species effused or circumambient, crowded, sessile, subglo- 
bose, smooth, white, outer peridium crustaceous, like the shell 
of some small egg. He finds the spores globose, black, about 13y. 
in diameter. 
Macbride’s description is accurate for the specimens which 
we have. We have collections from Blue Mounds, August 18, 
1903; from Eagle Heights, Madison, August 31, 1904; another 
from Madison, no date; and one from Devil’s Lake July 14, 
1906, on very much decayed leaves. 
Diderma, liemisphericum (Bull.) Horne. 
1791. Reticularia hemispherica Bull., Cham,, de Fr. f I., p. 93. 
1829. Biderma hemisphere cum (Bull.) Horne, FI. Ban., XI., p. 
18. 
Macbride: “Sporangia gregarious, orbicular, discoid, de¬ 
pressed above and often umbilicate below, stipitate or sometimes 
sessile, the outer peridium white, fragile, crustaceous, soon break¬ 
ing about the margins, closely applied to the inner, which is deli¬ 
cate, cinereous, and ruptures irregularly; stipe about equal to 
the diameter of the sporangium, 1 mm., rather stout, calcareous 
but colored, brownish or alutaeeous, more or less tvrinkled longi¬ 
tudinally, the wrinkles when present forming veins on the lower 
surface of the sporangium: hypothallus small; columella not dis¬ 
tinct from the thickened brownish or reddish base of the sporan¬ 
gium ; capillitium of delicate threads, mostly simple and color¬ 
less, often scanty; spores pale violaceous, nearly smooth, 8-9 ^. 99 
Macbride adds that this is a well-marked species > easily recog¬ 
nized by its remarkable discoid or lenticular sporangia in the 
stipitate type. 
Lister’s description differs but little from Macbride’s. He 
says the plasm odium is white, the sporangium scattered, rarely 
confluent: often seated on a white hypothallus: spores pale vio¬ 
let-brown, almost smooth, 7-9/x in diameter. 
Massee calls the stem pale ochraceous or whitish; columella 
