342 MuRRILL: POLYPORACEAE OF NORTH AMERICA 
is therefore a synonym of Mucronoporus and Coltricia. As to the 
standing of such genera as Hymenochaete and Mucronoporus, based 
solely on the presence of cystidia, opinion has been divided, but 
a brief study of various forms will show that this character is pos- 
sessed exclusively by no one group of fungi and that it varies 
abundantly even within the limits of a single species. It often 
affords a convenient clue to the identification of species, but should 
be accompanied by stronger and more permanent characters in the 
separation of genera. 
The species of the present genus are terrestrial or wood-loving 
plants found in dry soil in woods or attached to decayed sticks or 
roots beneath the ground or growing at times upon much-decayed 
logs and stumps. Some of the species have a peculiar fondness 
for places where fires have been built; others are able to adapt 
themselves to very varied localities, growing now upon rich soil 
and again upon dead standing tree-trunks. In appearance, they 
are usually circular, central stemmed, brownish plants with rusty 
context and spores and a brown hymenium, which is covered with 
a yellowish or whitish powder when young. Cystidia are rarely 
present. The consistency of the pileus varies from coriaceous to 
spongy and the surface from concentrically zonate to smooth. 
As to distribution, the members of the genus are about equally 
divided, half of them being cosmopolitan and the other half local. 
The smallest plant of the group is C. cianamomea, the largest C. 
Memmingeri, a new species known from one locality only. 
Synopsis of the North American species 
1. Pileus concentrically zonate, context thin a 
Pileus azonate, context rather thick and spongy. © 
vs Fileus shining cinnamon, strigose, striate, thin, flexible, slightly asia pike the mar- 
often fimbriate or pseudo-ciliate . C. cinnamomee- 
Pileus dull rusty cinnamon to hoary, velvety to glabrous, nt depressed, the 
margin thicker and less fimbriate 3: 
3. Tubes small, 0.5 mm. or less in diameter. 2. C. perennis. 
Tubes large, I mm. in diameter. 3. C. parvula 
4. Context homogeneous, hymenium free from spines 5 
Context duplex, soft above and woody below, Ssiocaitare beset with spines 
A. Gs mean 
5. Pileus ferruginous to fulvous, 5 cm. in diameter, surface finely tomentose, stipe 
swollen and soft at the base. 5. Co 
ileus darker, fulvous to chocolate-colored, 10 cm, in diameter, surface rough and 
shaggy, stipe scutate and firm at the base, 6. C. Memminger- 
