24:6 



Bulletin 193. 



iiiof would cease and an area around the knot would die back. Then 

 for another series of years tlie healing would begin and advance 

 over a portion of this dead area, wlien another period would inter- 

 vene durino; which a still o^i'eater area would die back. In this way 

 large and ugly open ulcers are formed, in which the wood within 

 is exposed. This condition is shown in photographs from young 

 maples. On a numl)er of these examples there were no fungus 

 fruit bodies, but a section of tlie trunk shows all the character of 

 the heart rot caused by the mycelium of Polyporus igniarius. 



.i^^t^K^^i 



80. — Fruit bodies of Polyponis pinicola on red spruce. 



The Polyporus igniarius Jias been known for a long time to 

 inlial)it fruit trees, especially the apple, peach, etc., under certain 

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

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

 this polyporus on 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. 



