42- 



DISEASES OF ECONOMIC PLANTS 



The pore-bearing sporophores are hoof-shaped, smooth 

 above, and concentrically ridged and gray. Below they 



are red-brown. 



Rot {Fom.es ap- 

 planatus (Pers.) 

 Wallr.). — The 

 shelving, pore- 

 bearing sporo- 

 phores are very 

 large, woody, and 

 grayish to brown 

 above, and are 

 commonly found 

 on dead wood, 

 more rarely upon 

 live trees. 



Rot (Poly- 

 porus pinicola 

 (Schwartz) Fr.). 

 — The causal 

 fungus is of 

 world-wide dis- 

 tribution upon 

 conifers, espe- 

 cially spruce, 

 pine, fir, and hemlock. It occurs also upon birches and 

 other deciduous trees. Entrance is made through wounds 

 of any kind. The rotted wood is brittle, cracked, and 

 permeated by numerous sheets of myceUum. In early 

 stages of decay it passes through red-brown to dark-brown, 

 then small, white areas of numerous shapes and irregu- 



•Fomes applanatus upon trunk of deaf 

 After Freeman. 



