Bui 32, Bureau of Plant Industry, U. S. Dept. of Agriculture 



Plate IV. 



Disease Caused by Polyporus fraxinophilus. 



1, Transection of ash wood; 2, transection of medullary ray; 3, medullary ray, showing later 

 stage of fungus attack; 4, 5, transection of wood cells; 6, starch grains from medullary ray 

 cell; 7, starch grains from diseased wood; 8, transection from entirely rotted wood. 



