8o PRACTICAL TREE REPAIR 



white to light yellowish in color, according to the 

 species of tree in which the fungus Is growing. 

 When rubbed betw^een the fingers it breaks up into 

 fine flakes, but does not powder." 



The fungus does not normally develop sporo- 

 phores until many years after infection. The 

 woody fruiting body, though somewhat variable 

 in appearance, is usually hoof-shaped, with a hard 

 outer layer, brownish or blackish in color. To 

 the lower surface of the hoof there is annually 

 added a gray or reddish-brown layer of pores in 

 which are produced the spores which reproduce 

 the fungus. The first sporophores usually appear 

 at the point of original infection. Later ones 

 may break out wherever the decay comes close to 

 the surface of the wood. The sporophores are 

 by no means so common as the rot. In many 

 groves of infected trees not a single sporophore 

 will be found. 



A decay of which the sporophores of the causal 

 fungus are more familiar than those of the fungus 

 just described is the red heart rot induced by 

 Polyporus sulphureus. It attacks both coniferous 

 and deciduous trees, particularly the oak, chestnut, 

 walnut, maple, apple, pear, and hemlock. Wood 

 destroyed by this fungus becomes red-brown and 

 full of checks, in all three planes, which fill with 

 white sheets of mycelium. Later the powdery 

 remains of the wood can be shaken out, exposing 



