i66 TIMBER AND SOME OF ITS DISEASES, [chap. 



the substance a coral-like appearance. I have often 

 seen it in the neighbourhood of Englefield Green 

 and Windsor, and it is very common in England 

 generally. 



If the spore of this Polyporus lodges on a wound 



Fig. i8. — Piece of timber infested with the mycelium oi P. suljihurens : t\i& white 

 masses of fungus fill up the rings and rays produced by their ** rotting" action. 

 (After Hartig.) 



which exposes the cambium and young wood, the 

 filaments grow into the medullary rays and the vessels, 

 and soon spread in all directions in the timber, 

 especially longitudinally, causing the latter to assume 



