The Biology of Polyporus Pargamenus Fries 49 
the margin when bruised is not a constant character, its 
mention as a general occurrence does not fortify the deserip- 
tion but is misleading. With this character thrown out of 
consideration a portion of the material at the writer’s dis- 
posal agreed fully with the portion of the type specimen of 
Coriolus subchartaceus. Still other specimens at the writer’s 
disposal, however, departed markedly from the type material 
of C. subchartaceus in that the pile were laterally elongated 
and effused, and almost equilaterally triquetrous in sectional 
outline. At the rear of these pilei the tubes were more or 
less thin-walled and lacerate, and attained a length of five 
mm., becoming progressively shorter toward the margin 
where they remained thick-walled and entire. 
The writer has collected similar laterally elongate, trique- 
trous, thick-walled, poroid forms of Lenzites sepuaria on 
fallen trunks of lodgepole pine in Montana, and has come to 
regard such extreme forms as the ecological growth form of 
these plants in response to xerophytic conditions. 
While the poroid form, including its many varieties 
departs markedly in many respects from the typical hydnoid 
Polyporus pargamenus, it still bears considerable resem- 
blance to it. The hymenial elements are very similar in both 
forms. In the various poroid forms studied, however, rd 
dia predominatingly capitate with minute crystals (Fig. 1, 
p- 50) as described by Overholts (4 915), were invariably 
present; similar cystidia also occur in the typical hydnoid 
forms of Polyporus pargamenus, but usually less abundantly 
than in the poroid forms. 
The usual type of the poroid form of Polyporus parga- 
menus has sufficient morphological characters in common 
with the well-established hydnoid form of P. pargamenus 
that it has been included with it by practically all mycolo- 
gists who have worked with it. Moreover the macroscopic 
characters of the decayed wood are the same in both cases. 
On the other hand, the differences between these two forms 
are vastly more pronounced than those between a number 
of our other closely related accepted species and the poroid 
form could rightfully be set aside as a distinct species as 
