Bu . 149, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



PLATE 



' 1 



> 



FIG. 1. CROSS SECTION OF THE TRUNK OF A LIVING SILVER MAPLE ROTTED BY 



FOMES IGNIARIUS. 



FIG. 2. CROSS SECTION OF A LIVING ASPEN TREE ROTTED BY FOMES IGNIARIUS. 



