HYDNUM 



389 



tubercles here and there, bearing long spines on the under 

 surface up to i inch in length, spines often flattened, tips 

 fimbriate. 



Thiimen, Zeitschr. Pflanzenkr., vol. i. p. 132. 



Oak rot (Hydnum diversidens, Fries.) causes a white-rot of 

 the wood of oak, beech, elm, birch, etc. It is a rare fungus 



FIG. 121. Hydnum scheidermayeri. Fungus, about 

 one-quarter nat. size. 



in this country. I have only met with it once, on a living 

 beech in Epping Forest. It is a wound-parasite, entering 

 through a broken branch and rapidly spreading in all direc- 

 tions. Wood attacked by the mycelium assumes a reddish- 

 brown colour first ; soon, however, the spring wood of each 



