THE BIOLOGY OF POLYPORUS PARGAMENUS 
Fries.* 
ARTHUR S. RHOADS. 
Introduction. 
Polyporus’ pargamenus Fries is one of the numerous fungi 
~ which cause the rotting of wood. Its small sporophores are 
to be found during all months of the year on living trees, 
dead trees, and fallen woody parts in moist situations. Even 
in winter its sporophores begin to grow with every warm 
spell of weather. Under the climatic conditions of the 
eastern United States, however, it is especially during the 
autumn months that the sporophores appear in great abun- 
dance. This fungus is one of the familiar objects to the 
field mycologist, but its life history, morphology, and ecology 
seem hitherto to have been neglected. 
Deciduous forest trees are effected with an unusually large 
number of different fungous diseases, some of which are 
assuming more and more importance daily. In dealing with 
our timber tracts, whether they be wood-lots or larger areas, 
it is becoming of increasing importance to take cognizance 
of those factors which entail a marked depreciation in the 
1A thesis submitted to the faculty of The News York State College of 
Forestry at Syracuse University in partial fulfillment of the require- 
ments for the degree of Doctor of Philosophy, May 1, 1917. 
*' The writer has deemed it advisable to drop the generic name Poly- 
stictus as a designation of a section of Polyporus for two reasons: 
First, because it is a synonym of Coltricia Gray, which was proposed 
several years earlier, and second, because it is not a well-defined genus, 
there being too many intermediate species to permit of its being longer 
used. This digression should cause no confusion since the names Poly- 
porus and Polystictus have been used almost. interchangeably with 
reference to the thin coriaceous plants once segregrated under the latter 
name. 
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