Dean—The Myxomycetes of Wisconsin. 
1249 
Didenna spumarioides Fries. 
1892. Diderma spumarioides Fries, Syst. Myc., III., p. 104. 
Macbride: “Sporangia sessile, crowded, spherical, or by mu¬ 
tual pressure irregular, white; the peridium plainly double, but 
the layers adhering, the outer more strongly calcareous, but very 
frail, almost farinaceous; hypothallus more or less plainly in evi¬ 
dence, white or pale alutaeeous; columella distinct though often 
small, globose, yellowish; capillitium variable in quantity, some¬ 
times abundant, brown, somewhat branching and anastomosing 
outwardly, the tips paler; spores minutely roughened, dark vio¬ 
laceous, about 10/*.” He says that although this species has the 
outward appearance of a Didymiuw ,, the crust is made up of 
minute granules of lime, not crystals. 
Lister describes the hypothallus as strongly developed and 
white: the columella convex or hemispherical, white or pale 
flesh-col ored; spores spinulose, 8-10 y. 
Massee adopts the name Bidymium spumarioides Fr. He 
finds the columella sometimes almost obsolete ; spores warted, 
9—12 a. 
Macbride’s description is as a whole adequate, but I fail to 
see the “peridium plainly double. 7 ’ This might be Physarum 
cinereum, but that it has a columella in most sporangia, and has 
no calcareous nodes in the capillitium—these characteristics mak¬ 
ing a vital distinction, of course. I find the spores dark purplish, 
distinctly warted, and quite uniformly 10/x in diameter. 
We have one collection, made at Devil’s Lake, July 15, 1905, 
growing on a green moss and its ripe sporophyte setae; another, 
having many variations of form, cn dead leaves, from the campus 
woods, July 1904. 
Biderma globosum Per so on. 
1794. Biderma globosum Pers., Rom. N. Mag. Rot., I., p. 89. 
Macbride: “Sporangia more or less gregarious, sessile, globose, 
or by mutual pressure prismatic or polyhedral, white, the outer 
wall smooth, polished, crustaceous, fragile, far remote from the 
inner, which is thin, smooth or rugulose, irrideseent blue; hypo¬ 
thallus usually pronounced and spreading beyond the sporangia, 
