430 THE FUNGI WHICH CAUSE PLANT DISEASE 



and finally black and shining with age, zonate, sulcate, homy- 

 encrusted; margin obtuse, velvety, isabelline to fulvous; context 

 punky, homogeneous, ferruginous to fulvous, conidia-bearing, 

 3-5 mm. thick; tubes indistinctly, stratified, not separated by lay- 

 ers of context, 3-5 mm. long each season, avellaneous to imibrinous 

 within, mouths circular, whitish-stuffed when young, 3-4 to a mm. ; 

 edges obtuse, entire, grayish-white to avellaneous, turning dark 

 when bruised: spores globose, smooth, very light brown, 3-4 fi; 

 hyphae brown, 7-8 n; cystidia none. 



The mycelium kills the cambium and causes a white rot of the 

 sap wood of deciduous trees, especially beech, birch, elm, maple. 

 The wholly rotted wood is soft, and spongy, light yellow and 

 crumbles into its separate fibers. 



F. everhartii (E^ & G.) *^' " ( =Pyropolyporus praerimosa). 



Pileus woody, dimidiate, ungulate, broadly attached behind, 

 6-10 X 6-15 X 3-8 cm. ; surface glabrous, slightly encrusted, deeply 

 sulcate, not polished, gray to brownish-black, slightly rimose 

 in age; margin obtuse, covered with ferruginous tomentum, be- ■ 

 coming gray and glabrous: context corky to woody, repeatedly 

 zoned, fulvous in dried specimens, 2-3 cm. thick; tubes evenly 

 stratified, 0.5-1 cm. long each season, fulvous, mouths circular, 

 4 to a mm., edges rather thin, entire, ferruginous to fulvous, 

 glistening, the hynjenivrai becoming much cracked in age: spores 

 globose, smooth, ferruginous, 3-4.5 /t; spines abundant, pointed, 

 larger at the base, 15-25 x 6-10 /t. 



On black oaks, and walnuts ''" causing a rot almost indistin- 

 guishable from that caused by F. igniarius. The mycelium 

 often grows into the living sap wood. 



F. cameus Nees."' ^ 



Pileus woody, dimidiate, varying from conchate to ungulate 

 often imbricate and longitudinally effused, 2-4 x 6-8 x. 0.5-3 cm.; 

 surface rugose, subfasciate, slightly sulcate, rosy or flesh-colored, 

 becoming gray or black with age; margin acute, becoming obtuse, 

 sterile, pallid, often undulate; context floccose-fibrose to corky, 

 rose-colored, 0.2-2 cm. thick; tubes indistinctly stratose, 1-2 mm. 

 long each season, mouths circular, 3-4 to a mm., edges obtuse, 

 concolorous; spores ellipsoid, smooth, thick-walled, subhyaline, 

 3.5 X 6 M- 



