J 



FIG. 48. Transverse section of oak timber destroyed by 

 Polyporus sulphureut. (K. Hartig.) 



FIG. 49. Highly magnified longitudinal radial section of 

 a piece of oak destroyed by a timber fungus, showing 

 the ravages of the hyphae in the various tissues. (R. 

 Hartig.) 



M 2 



