202 



193. 

 POLYPORUS BOREAUS. 



Polyporus borealis occurs on pines, spruces, the hemlock, etc., 

 and is widely distributed over the North Temperate Zone. It 

 occurs on living or dead trees. It is a "wound" parasite, 

 entering through broken branches, through wounds caused by 

 impact of falling timber, or where the cambium has been 

 scorched by fire. The fruit bodies are entirely white. When 





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-: 



58. Polyporus borealis, Hymenium with sinuous pores. 



old or dry they often take on a pale yellowish tinge. They are 

 shelving, the cap attached directly to the tree, broad at the free 

 end and tapering somewhat in a wedge-shaped manner toward 

 the base. They are rarely single, and sometimes scattered over 

 the trunk. They usually occur, several close together overlap- 

 ping in an imbricated fashion, and joined at the base in a common 

 trunk at the exit from the tree. 



