48 College of Forestry 
continuance of the growth of the pileus. In this particular 
case it does indicate that the pileus is ecologically adapted 
to living and developing under xerophytic conditions which 
often are such as to temporarily arrest all growth of the 
pileus. 
Lloyd (1917) recently has commented on a specimen of 
this poroid form on Populus sent him by Dr. J. R. Weir, as 
follows: 
“NOTE 536.— Trametes pergamena, from James R. Weir, 
Montana. A thick, trametoid form of Polystictus pergamenus. 
The Fresian system of genera for the large fungi is probably the 
best, but it is embarrassing when species assume forms that place 
them in two genera. The common Polystictus pergamenus of our 
Eastern States is our only polyporoid (excepting P. abietinus) 
that has violaceous pores. The Western form found on Populus 
trichocarpa by Mr. Weir, is a thick, rigid plant, but in other 
features context, large violaceous pores, etc., is that same species. 
It was recently named Polystictus subchartaceus.” 
The poroid form on species of Populus throughout the 
West 1s extremely variable and at times looks quite distinct 
from the poroid form on species of this same genus in the 
East. As a general rule the western specimens are much 
thicker than the eastern, often becoming a centimeter or 
more in thickness. The upper surface usually is hirtose- 
tomentose and is marked by more or less distinct, often 
heterogeneously colored, sulcations which are indicative of 
the periodic increment made by the pileus during its devel- 
opment. The pores, which are at first thick-walled, become 
thinner-walled and more or less lacerate with age. A part 
of the western material examined agrees closely in its macro- 
scopic characters with Coriolus subchartaceus Murrill, as 
evidenced by its comparison with a portion of the type col- 
lection of this plant which was kindly furnished the writer 
by Dr. Murrill. The most striking disagreement was in the 
absence, in the writer’s material, of the shrunken blackish 
margin present in the authentic material. As a matter of 
fact this shrunken, blackish margin present in the type 
specimen was undoubtedly caused by the collection of the 
specimen before the marginal portion had fully matured. 
The writer therefore considers that, since the blackening of 
