44 College of Forestry 
two species fails to furnish additional characters for their 
separation, other than on the occurrence of cystidia. In 
general it may be stated that in the usual hydnoid form of 
P. pargamenus eystidia are of infrequent occurrence, whereas 
P. abietinus apparently always is characterized by abundant 
prominent cystidia that are distinctly capitate with minute 
crystals. The poroid forms of 2. pargamenus, however, like- 
wise have the same type of cystidia that commonly occur in 
P. abietinus. The spores of both species agree as to their 
size and shape. ; 
These two species then are to be distinguished definitely 
only by the combined use of such characters as the form of 
the pores and the size, shape, and general appearance of the 
pileus. In most cases they can be separated by their habitat 
alone. The writer’s collecting experience, however, has 
shown that the latter character is not always enough to sepa- 
rate them. When once the two plants are learned the matter 
of form and surface characters will usually be sufficient for 
the identification of the specimens, even if the habitat be 
unknown. 
MorpimoLogy or THE SPOROPHORE. 
Form of the Sporophore.— The sporophores of Polyporus 
pargamenus vary greatly in size and shape, the resupinate 
forms often covering the whole under side of a log (Plate V). 
The sporophores, however, usually are pileate. Neuman 
(1914) states that his largest specimen is about ten em. wide, 
five em. long, and from 2—4 mm. thick. Although the pileus 
invariably is sessile, the form of the sporophore is variable, 
depending upon its habitat. When the pilei develop from the 
base of a tree they usually are narrowly attached by cuneate 
bases. When the substratum is well above the ground they are 
more broadly attached. When the sporophores develop from 
a standing tree or from the upper half of fallen stems they 
usually become shelving However, upon one occasion 
entirely resupinate sporophores were found on the standing 
dead trunk of a black oak (Quercus velutina Lam.), while 
