410 Wisconsin Academy of Sciences , Arts , and Letters . 
apiculate spores 6—7x8—12^, with an apical pore covered 
by a hyaline papilla. There are four principal forms in the 
group, Hypholoma velutinum, rugocephalum, boughtoni 
and pyrotrichum. Photographs of Hypholoma velutinum 
were published in vol. XVII, pi. LXXIX. Since then we 
have collected Hypholoma rugocephalum and Hypholoma 
boughtoni. They grow on the ground in open woods at 
Geneseo, Ills. All four species have the spores exactly alike 
in size and character, see vol. XVII, pp. 1153-1154. The 
chief difference in the plants is in the surface of the pileus. 
It is matted fibrous in Hypholoma velutinum, innate fibrous 
and concentrically cracking in Hypholoma boughtoni, 
somewhat viscid and rugose wrinkled in Hypholoma rugo¬ 
cephalum and matted fibrous and bright fiery tawny in 
Hypholoma pyrotrichum. All these species appear to be 
closely related and the differences due chiefly to age and 
weather conditions. 
1. Hypholoma rugocephalum Atk. PI. XX. 
The plants were found at Geneseo, Ills., in open woods. 
The plants are larger than either Hypholoma velutinum or 
Hypholoma boughtoni. The pilei were innate fibrous when 
young becoming glabrous, slightly viscid and rugose wrinkled. 
They were at times somewhat cracked near the margin 
showing close affinity with Hypholoma boughtoni. The 
other characters were exactly those of the group. Atkin¬ 
son’s description is as follows. Mushrooms, p. 30, fig. 29. 
Pileus convex to expanded and revolute, marked with 
radiating rugose, wrinkles, broadly umbonate, fleshy at the 
center, thinner toward the margin, slightly viscid, smooth, 
not hairy or scaly, the thin margin, extending beyond the 
gills, fulvous-tawny. Flesh tinged with yellow. Lamellae 
adnate, slightly sinuate, 5—7 mm broad, easily breaking 
from the stem and then rounded at the base, spotted with 
black spores, lighter on the edge. Spores black in mass with 
a slight purple tinge, oval to broadly elliptical, inequilateral, 
pointed at each end, echinulate or minutely tuberculate 
8—11x6— 8g. Basidia short, cylindrical, Cystidia cylin¬ 
drical, somewhat enlarged at the free end, delicate, thin 
walled, in groups of 2—6 or more. Stem cylindrical, even, 
somewhat bulbous, colored like the pileus, lighter above the 
annulus, irregular, smooth, fleshy, hollow, continuous with 
