106 



MANUAL OF TREE DISEASES 



the activities of the fungus, the wood is reduced to a soft, light 

 yellowish punk. Black lines are formed between the decayed 

 and luiaffected wood in places, or they may persist in the com- 

 pletely decayed portion. The rot extends into the heartwood 

 toward the center of the tree. Where splits or checks occur in 



the decayed portion, a chamois- 

 like sheet of closely woven yel- 

 lowish mycelium is formed 

 which fills the space and can 

 with care be removed in large 

 pieces. Trees are usually first 

 affected in the upper half. 



The sporophores or punks of 

 this fimgus, which are formed 

 on the trunks of affected trees, 

 usually occiu" in large nimibers 

 on each tree, the number vary- 

 ing with the extent of the de- 

 cay. The sporophores are not 

 confined to old branch wounds 

 as usually is the case with 

 heartwood-rotting fungi, but 

 emerge from apparently unin- 

 jured bark of the trunk. They 

 are easily recognized, being dis- 

 tinctly hoof-shaped and light to 

 dark gray on top. The lower 

 surface is light brown, with 

 rather large regularly arranged circular pores. Both surfaces 

 are smooth and velvety when young. A new layer of tubes is 

 added each year, which extends beyond the previous year's 

 growth, producing an arched ridge (Fig. 11). The margin 

 of the sporophore is rather thin and the tube-surface is some- 

 what concave. 



Fig. 11. 



— Fruiting-body of Fames 

 fomentarius. 



