334 MURRILL : POLYPORACEAE OF NORTH AMERICA 



last only G. cristata is congeneric with the type, the others belong- 

 ing to Polyporus and Ganodcrma. In Karsten's arrangement of 

 the group, P. frondosus with P. confluens and P. sulfureus form the 

 basis of a new genus, Polypilus, Gray's genus Grifola not being 

 considered. So, again, Quelet establishes his genus Cladomeris on 

 P. umbellatus and sixteen other species, ignoring the work of both 

 Karsten and Gray. 



The plants of the genus Grifola are large and striking in appear- 

 ance and sometimes attractive in coloring. They are intricately 

 branched or irregularly lobed, fleshy or fleshy-tough in substance, 

 with white context and spores and large, irregular tubes, which 

 become friable or laciniate with age. They are usually found on 

 or near dead wood in some form, either attached to buried sticks 

 or roots or growing close to the base of a tree trunk. This latter 

 habitat is a favorite one for at least four members of the genus, 

 and the tree is usually an oak. 



The distribution of members of this genus is quite general. 

 Two of our species occur also in the Eastern hemisphere and two 

 others are represented there by nearly related plants. G. frondosa 

 may be said to be abundant, G. poripes and G. Berkeleyi are fairly 

 well known and the remaining three are rare, G. ramosissima being 

 more common, however, in Europe than in America. 



Owing to the difficulty of handling such large forms and the 

 changes which they undergo in drying, many mistakes are current 

 concerning these plants. It is not easy to gain a just conception 

 of an entire plant from one of its minute divisions, and in this, as 

 well as in other groups, form and habit of growth count for much. 

 If some of the existing errors have been eradicated by these studies, 

 there is yet much to learn with regard to known species and more 

 concerning those whose standing is still in doubt. 



Synopsis of the North American species 



1. Hymenium ochraceous, becoming dirty-yellow with age, plants terrestrial, irregularly 



confluent, olivaceous to greenish-yellow. I- G. poripes. 



Hymenium at first fuliginous, becoming paler. 2. G. Sumstinei. 



Hymenium white or pallid from the first. 2 - 



2. Surface of pileus gray or grayish-brown to coffee-colored, stipe intricately branched, 



pileoli very numerous and small. 3- 



Surface of pileus pallid or alutaceus, stipe not intricately branched, lobes usually few 



in number and comparatively large. 4- 



