234: 



BULLETIX 193. 



conifers. It is known on the apple, walnut, butternut, locust, oak, 

 ash, pine, hemlock spruce, and other trees. It occurs un living 

 trees, the fruit bodies growing from knot holes or wounds from the 

 mycelium in the heart of the tree ; or the fruit bodies arise from 

 portions of the trunk killed bv the fungus. It is also a very com- 

 mon fungus on dead and decaying logs, stumps and roots. 



The plant is easily recognized by 

 the yellowish color of the caps wliicli 

 are of the shelvino- form, sometimes 

 scattered, but more often closely 

 over-lapping. Sometimes the caps 

 are so closely crowded as to form a 

 laro'e tubercle 20 to 25 cm. or more in 

 diameter. The upper surface of the 

 cap is a bright orange red, Avhile 

 the lower surface, the honey-combed 

 fruit surface, is sulphur yellow. The 

 fruit bodies are rather^ soft, the 

 color soon fades, they are cpiickly 

 attacked by insects, or decay a,fter 

 several weeks. They are short lived 

 therefore, while the mvcelium within 

 the trunk is perennial, or at least 

 ^.—lUyporm ^ulphureus. Large lives from year to year without an 

 tubercular fruit bod?/ on oak. annual infection. 



Oak Tree Killed by Polyporus Sclphureus. 



A scarlet oak tree {Quercus cocchiea) growing near the grounds 

 of Cornell University was under observation for several years. 

 The tree was standing on the edge of the Fall Creek gorge, not far 

 from the Fisk McGraw mansion and opposite the present electric 

 power plant of the Ithaca Street Railway. It was first observed in 

 1897. At this time the mycelium of the sulphur polyporus had 

 advanced so far from the heart wood into the sap wood that the 

 latter, as well as the cambium layer, on one side of the trunk near 

 the base, had been killed. This gave an opportunity for the exit of 

 the fungus, and the formation of the fruit bodies on the outside. 



