378 DISEASES OF CULTIVATED PLANTS 



Differs from Fames in the soft consistency, pores not 

 stratose, and in being annuals from Polystictus in not 

 having the pileus velvety and colour-zoned, and in the 

 thicker flesh : from Poria in not being entirely resupinate. 



Heart- wood rot. This is caused by Polyporus hispidus 

 (Fries.), a wound-parasite, which is very injurious to fruit-trees, 



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FIG. 116. Polyporus hispidus. Fungus and section much reduced. 

 Two basidia bearing spores, highly mag. 



apple, pear, plum, etc. ; it also attacks other trees, more 

 especially the ash. Prillieux says that it is not uncommon on 

 mulberry trunks in the Cevennes. This is one of the poly- 

 pores that destroys the heart-wood, and begins its work in 

 the wood near to the pith. From this point the disintegra- 

 tion of the trunk extends outwards towards the sap-wood. 

 The decomposed wood a whitish colour tinged with rose, and 

 is very friable, and the trunk eventually becomes hollow. A 



