DISEASES OF BOOTS, ETC. 49 



limb, when their shape is that of a broad bell. The en- 

 tire fruiting body is light tan color, though the under- 

 side is slightly lighter than the upper. The latter is 

 smooth and distinctly velvety to the touch, especially 

 toward the margin. The pores of the underside are 

 rather small. The substance of the fruiting body va- 

 ries in color from tan to brown. The fungus causes a 

 destructive heart-rot, which is characterized by coarse, 

 dark-brown, and yellowish- white fibers. 



FALSE TINDER FUNGUS. 



The false tinder fungus (Fames igniarius, PI. XV) 

 is confined to deciduous trees, and is especially common 

 on willows, cottonwood, and quaking aspens. It causes 

 a white heart-rot which sometimes extends into the 

 sapwood. If only the heartwood is destroyed, the tree 

 may live for many years, until it is finally broken off 

 in a storm or heavy snowfall. When the living sap- 

 wood becomes diseased, however, the damage is more 

 serious. While the perennial fruiting bodies do not 

 grow in groups, a number may appear on the same tree, 

 issuing from branch scars. They are hard and usually 

 hoof-shaped. In size they vary a good deal, but are 

 rarely very large. When young the upper side is vel- 

 vety and brown, and when old, dull brown to almost 

 black, concentrically furrowed and cracked. The mar 

 gin is velvety and of a lighter rust-brown. The under- 

 side is a grayish rust -brown to cinnamon, with small 

 pores. On the smooth, light bark of the host tree the 

 dark fruiting bodies stand out very conspicuously. The 



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