394 PLANT DISEASES 



whitish ; pores at first pure white, about J cm. long, 

 medium size; spores colourless, elliptic-oblong, 6x4 /*. 



Biscuit-like sporophores, entirely white, are often formed 

 on subterranean roots. 



Fomes ribis, Fries, Syst. Myc.^ i. p. 375. Imbricated, 

 horizontal, coriaceous, rigid, flattened, almost even, fer- 

 ruginous, velvety, margin acute, base often thinner than 

 the margin, 6-10 cm. across ; flesh thin ; tubes about 2 mm. 

 long, pores minute, tawny. 



Poria, Pers. Entirely resupinate, forming more or less 

 extended patches or thin membranaceous expansions, often 

 inseparable from the matrix ; pores covering the entire 

 surface except the extending margin. 



Poria vaporaria, Fries, Syst. Myc., i. p. 382. Broadly 

 effused, thin, inseparable, the white mycelium penetrating 

 the matrix ; pores large, angular, or inclined to be sinuous, 

 often oblique, dissepiments often eroded ; entire fungus 

 white, then straw-colour or ochraceous. 



Trametes, Fries. Sporophore corky or woody, dimidiate 

 or resupinate; pores roundish, often elongated radially; 

 dissepiments rather thick, unequal in depth, and not 

 forming a heterogeneous stratum, hence the trama is 

 continuous with the flesh of the sporophore. 



Trametes pini, Fries, Syst. Myc., i. p. 336. More or 

 less semicircular in outline, horizontal, attached by a broad, 

 thick base ; pileus rusty-brown, then blackish, concentric- 

 ally sulcate, rough, margin strigose ; flesh rusty, hard ; 

 pores irregular in form, deep and indistinctly stratified in 

 old specimens, bright ferruginous with a yellow tinge, 

 becoming dusky. 



