240 



Bulletin 193. 



The upper surface is marked by concentric furrows and ridges 

 wliich mark off the annual layers. The fungus is thus perennial. 



73. — Polyporus igniarius, from maple. 



It is very generally distributed through hardwood forests. It is 

 especially abundant in certain hardwoods in the Adirondacks. In 

 some sections a large percentage of the beech, birch and maple is 



affected. A quantity of 

 the wood of affected trees 

 was collected both at 

 C h i 1 d w o o d , St. La w- 

 rence Co., in 1896, and at 

 Clearwater, TI e r k i m e r 

 Co., in 1898. At the lat- 

 ter place, the second flag 

 station north of Fulton 

 Chain, on the E". Y. C. R. 

 R., there were excellent 

 opportunities for studying 

 it on the maple, and for de- 

 terminino; the conditions 

 which favor the entrance 

 of the fungus into the 



•7/f Q^t.' ^ j>j- V 7 7 V? r) 7 • • • heart of the tree. Since 



/4. — Section of friiit body of Polyporus igniarius. 



the mycelium cannot enter 

 through the living cambium of the tree, an " infection court " must 



"m 



