SHADE TREE AND TIMBER DESTROYING FUNGI. 221 



are formed, in which the wood within is exposed. This condi- 

 tion is shown in photographs from young maples. On a number 

 of these examples there were no fungus fruit bodies, but a sec- 

 tion of the trunk shows all the character of the heart rot caused 

 by the mycelium of Polyporus igniarius. 



The Polyporus igniarius has been known for a long time to 

 inhabit fruit trees, especially the apple, peach, etc., under certain 

 conditions. During August, 1900, I observed an apple tree by the 



80. Fruit bodies of Polyporus pinicola on red spruce. 



roadside a few miles south of Cortland, N. Y., with fruit bodies 

 of this polyporuson it. A number of years ago the tree had 

 been pruned, by cutting several large limbs near the trunk, and 

 others out some distance from the trunk. The tree was probably 

 diseased at that time, and perhaps these limbs were dead or 

 dying. This may have led to their amputation. 



In all cases the fruit bodies of the fungus were formed at 

 these cut surfaces, there being no other place of exit. The tree 

 was probably seriously wounded when young, and the mycelium 

 entering had spread all through the heart of the trunk and 



