170 MANUAL OF TREE DISEASES 



west. Pine, spruce and other conifers are also sometimes 

 affected wherever these trees grow. The wood is discolored 

 and changes from bluish to yellowish and finally becomes 

 red-brown. White pockets with black centers appear in the 

 spring-wood of the rings. Later the pockets coalesce and the 

 brown summer-wood is left in separated sheets. The peren- 

 nial sporophores are shelving or resupinate and are found 

 attached to the diseased roots. The upper surface of the 

 shelving form is light brown and the under yellowish. For 

 further details concerning this root-disease, see under spruce 

 diseases on page 329. 



Red-Brown Root- and Butt-Rot 



Caused by Polyporus Schweinitzii Fries 



This root-rot occurs also on pine, larch, spruce, hemlock and 

 arbor-vitse throughout the range of these trees. It is next in 

 importance to the pecky wood-rot of conifers caused by Tra- 

 metes pini. The heartwood of the roots and lower part of the 

 trunk becomes at first yellowish and cheesy and later is red- 

 brown and brittle, resembling charcoal in structure. This 

 wood-rot is more fully discussed under pine diseases, on page 294. 



Yellow Root-Rot 

 Caused by Sparassis radicata Weir 



This yellow or brownish root-rot of fir, spruce, pine and larch 

 has been recently described as common in northwestern United 

 States. It seems to be equally as important in that region as 

 the shoe-string and brown root-rots, caused by Armillaria 

 mellea and Fomes annosus. The fungus causing the yellow rot 

 is peculiar in having a long perennial root-like attachment of 

 fungous mycelium which arises from the diseased roots. Other 

 species of the same group of fungi have been suspected of caus- 



