The Biology of Polyporus Pargamenus Fries 41 
Potyrorus ParGamenus Fries Versus Potyporus 
ABIETINUS FRIEs. 
Unfortunately Polyporus pargamenus frequently has been, 
and still is, confused with its near relative, Polyporus abie- 
timus. Many authors state that the former plant is confined 
entirely to the wood of dicotyledonous trees, while the latter 
plant is confined entirely to the wood of coniferous trees, 
and are of the opinion that this fact affords the only con- 
stant character by which they can be separated. The writer 
wishes to make clear that such an impartially drawn dis- 
tinction may generally, but will not always, separate these 
two closely related species, since Polyporus abietinus some- 
times occurs on dicotyledonous woods and P. parganenus 
sometimes occurs on coniferous species. Weir (1917) men- 
tions the occurrence of small but typical specimens of Poly- 
porus abietinus on Populus trichocarpa im the Northwest.” 
The writer (1917+) has made collections of Polyporus 
pargamenus from dead trunks of hemlock (T’suga cana- 
densis) upon several occasions both in New York and 
Pennsylvania. On one occasion he observed both plants 
growing side by side on the same dead hemlock trunk 
(Plate Il). Upon another oceasion a dead hemlock was 
literally covered with sporophores of Polyporus parga- 
menus alone, up to about eight feet above the base 
(Plate III). In every case where Polyporus  par- 
gamenus was observed growing on hemlock trunks the 
macroscopic appearance of the rot produced was indistin- 
guishable from that produced in this wood by Polyporus 
abietinus. Recently the writer (1918) collected specimens 
of both plants on a dead scrub pine (Pinus virginiana) trunk 
u Freeman (1905, p. 258) states that Polyporus pargamenus occurs 
abundantly on living larch (Laria laricina) trees in Minnesota, and 
gives an illustration (p. 81, fig. 36) of a larch trunk bearing numerous 
sporophores of what he takes to be this fungus. He states further that 
there is strong evidence of it having been the cause of the death of 
numerous larch trees in Minnesota. A careful perusal of Freeman’s 
work, however, shows that he does not distinguish between Polyporus 
pargamenus and P. abietinus, so that the case cited undoubtedly refers 
to P. abietinus. . 
