156 



THE OAK 



branches owing to the paucity of water at those parts, 

 the parasite taking much of that which reaches the 

 injured place, and the impoverished wood allowing less 

 to pass than it would normally have done. 



Among the fungi there are several enemies to the 

 oak-tree. The leaves are attacked by Phyllactinia, one 



FIG. 41. Loranthus europcBus. A. Lower part of stem 

 attached to branch of oak, both denuded of cortex. B. 

 Longitudinal section through one of the haustorial strands, 

 showing its progress, year by year, as the branch thickens. 

 C. Transverse section, through a branch which has long 

 been badly infested with the Loranthus ; a a, dead re- 

 mains of old haustorial strands ; b b, young Loranthus 

 plants developed as buds from the older ones. The 

 asterisks mark still younger specimens. (Hartig.) 



of the mildews, which forms white networks, like spiders' 

 webs, on their surfaces. Numerous small ascomycetous 

 fungi are found on the dying and dead leaves, but these 

 do not directly injure the living tree. 



Other fungi are found in the cortex, and one of the 

 most interesting of these is a red Nectria, the spores of 



