476 PROTECTION AGAINST FUNGI. 



the wood too much, and great care should be taken during 

 fellings to avoid wounds. Broken or forked branches, which 

 it is advisable to remove, should be sawn off cleanly and the 

 section tarred. 



Other Wound-Parasites attacking Oak and other Broadleaved 



Trees. 



All such fungi gain admission through wounds and broken 

 branches, so that they can be avoided by good silviculture. 



a. Polyporus dryadeus, Fr. 



White and yellow irregularly shaped longitudinal marks 

 appear in the wood, which at length becomes cinnamon- 

 coloured and rotten. The sporocarps are large, brown and 

 hoof-shaped, but do not last long. 



b. Polyporus igniarius, Fr. 



The commonest cause of white rot. Infected wood becomes 

 pale yellow and gradually lighter in colour and softer. The 

 tannin is at once attacked and decomposed by young mycelia 

 of this fungus, so that oak-wood loses its characteristic odour, 

 the absence of which is an excellent practical test of incipient 

 unsoundness. This fungus also occurs on fruit-trees and 

 other broadleaved trees. ' Sporocarps, hoof-shaped. 



P. betulinus, Bull, and P. laevigatus, Fr., cause red and 

 white rot respectively in birch, the former having roundish 

 sporocarps, and the latter, incrustations. 



c. Hi/dnum diver sidmx, Fr. 



Also causes white rot in oak and beech. The wood, and 

 especially its spring zones, turns ashy-grey, at first in stripes. 

 The sporocarps are yellowish-white incrustations or brackets. 



d. Thelephora perdix, R. Hrtg. 



Produces the well-known partridge-wood form of rotten- wood 

 (Rebkuhnholz), which is common in Germany, but not known 

 as British by Marshall Ward. The dark reddish-brown rotten- 

 wood becomes honeycombed with whitish blotches surrounded 



