Trees and Timber 



363 



(Q. marylandica and Q. velutina) are chiefly affected by this 

 rot, which is found in Missouri, Arkansas, Iowa, Tennessee, 

 Mississippi, New Jersey, and Maryland. 



Fig. 



190. — Tree weakened by Fomes fomentarius. 

 After Atkinson. 



The causal fungus enters through the burrows of a wood 

 borer. The heartwood turns light yellow, then white, 

 and becomes brittle. Strings and sheets of white mycelium 



