326 



MANUAL OF TREE DISEASES 



many irregular concentric folds. The under surface is light 

 brown and covered with minute holes which are the open ends 

 of the tubes in which the spores are borne. 



Caiise. 



Pecky wood-rot of conifers is caused by the bracket-fungus 

 Trametes jdni. This name was first applied to the shelving 

 form of sporophore and later the smaller resupinate form was 



Fig. 65. — Advanced stage of pecky wood-rot in longitudinal section. 



named Trametes pini abietis. This latter name is no longer 

 used, since the identity of the two forms has been established. 

 Like other fungi of the same group, the spores are formed in 

 perpendicular tubes on the under side of the sporophore. The 

 spores drop out of the tubes and are disseminated by the wind. 

 Infection may occur when these spores lodge on exposed heart- 

 wood, at 'broken branches or when the top of the tree is 



