SHADK TRKK AND TIMBER DESTROYING FUNGI. 209 



OAK TREE KILLED BY POLYPORUS SULPHUREUS. 



A scarlet oak tree (Quercus cocdnea} growing near the grounds 



of Cornell University 

 was under observa- 

 tion for several years. 

 The tree was stand- 

 ing on the edge of the 

 Fall Creek gorge, not 

 far from the F i s k 

 McGraw mansion and 

 opposite the present 

 electric power plant 

 of the Ithaca Street 

 Railway . It was first 

 observed in 1897. At 

 this time the mycel- 

 ium of the sulphur 



65. Polyporus sulphureus. Scattered fruit , , , 



bodies on living oak. polyporus had ad- 



vanced 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 out- 

 side. Fig. 65 is from a pho- 

 tograph taken in 1897. They 

 are fine specimens, but are 

 much more scattered than is 

 usual with this species. The 

 fruit bodies appeared during 

 the succeeding seasons of 1898 



and 1899. During the latter 



66. " Punk " in cracks on oak log. 

 season the tree died from the 



injuries of the mycelium in its advance on the cambium or living 

 portion of the trunk. It was felled, and several sections cut 

 out from the trunk for observation. 



