206 DISEASES OF TREES 



POLYPORUS FOMENTARIUS * 



The familiar tinder-fungus, which occurs on beeches and oaks, 

 produces a form of white-rot, and its mycelium has a tendency 

 to form luxuriant patch-like or skin-like growths in fissures of 

 the decayed wood. So far it has not been made the subject of 

 thorough investigation. 



POLYPORUS BETULINUS 1 ! 



Occasionally P. betulinus is to be found abundantly developed 

 on the birch. Its hirsute sporophore, which is white beneath and 

 brownish grey above, is at first globular, but afterwards takes 

 the form of an inverted bracket with a convex upper surface. 

 The decomposition induced by the parasite is a form of 

 red-rot. 



POLYPORUS L/EVIGATUS 2 



This parasite produces a form of white-rot in the birch. Its 

 sporophore appears on the surface of the bark as a dark brown 

 porous incrustation. 



Numerous other species of Polyporus doubtless occur as 

 parasites on the wood of trees, but these, so far, have not 

 been subjected to investigation. 



The following fungi are also worthy of mention. Dcedalea 

 quercina\ is met with everywhere on old oak-stumps, where 

 it forms large bracket-like sporophores which bear the hymenium 

 partly in pores and partly on lamellae. During decomposition 

 the oak-wood assumes a grey brown colour. Having found the 

 fungus vigorously developed on branch-wounds of the older 

 classes of oaks, I suspect that it is also a parasite. 



Fistulina hepatica. the Beef-steak Fungus, produces a deep 

 red brown decomposition in the wood of the oak: 



All the above-mentioned wood-parasites, which obtain an 

 entrance through wounds above ground, can only be combated 

 in one or other of the following ways. First, great care must be 



1 D. H. Mayr, Bot. Centralblatt, 1885. 2 Ibid. 



* [Common in Britain. ED.] 



f [1 have frequently collected this in this (Cooper's Hill) part of England. 

 -ED.] 

 % [Both this and the next occur in Surrey and elsewhere in Britain. ED.] 



