234 MANUAL OF TREE DISEASES 



on the top of the fniiting-bodies. It is commonly known as 

 the scaly or saddle-back fungus. Infection is effected by the 

 spores, which are wind-blown, lodging and germinating on 

 exposed wood, especially at broken or pruned branch stubs. 

 The less lignified elements of the wood-tissue are destroyed 

 and strands of mycelium fill the long channels thus opened up 

 in the wood. These strands run through the wood, replacing 

 the meduUary-rays and spring-wood, thus causing the white 

 bordered cubes which are seen in cross and longitudinal sec- 

 tions. The life history and control of the wood-rot fungi will 

 be found discussed on page 64. 



Referexces 



Sehrenk, Hermann von, and Spaulding, P. White-rot cleansed by 



Polyporus squamosus. In Diseases of deeiduous fdJest trees. 



U. S. Dept. Agr. Bur. PL Ind. Bui. 149 : 48-49. 1909. ' 

 Buller, A. H. R. The biology of Polyporus squamosus. Buds., a 



timber destroying fungus. Jour. Econ. Biology. 1 :'Hl-138, 



pis. 5-9, figs. A-P. 1906. 



Unifokm White Sapwood-Rot 



Caused by Hydnum septentrionale Fries 



A white sapwood-rot of maple and beech is occasionally 

 found in eastern and central United States. This rot has not 

 been studied and described and is not very important. The 

 affected wood is soft and uniformly white. Brown zones 

 separate the affected area from the normal wood. Black 

 lines are sometimes foimd running in various directions in the 

 rotted wood. 



The white fruiting-bodies of the fimgus are very conspicuous. 

 They are large, flat, fleshy structures often a foot or two long 

 and a foot across. They are composed of a thick sheet of 

 mycelimn adhering to the side of the tree with niunerous 

 closely overlapping projecting shelves. The individual shelves 



