428 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Fomes Fries (p. 417) 



Sporophore sessile, ungulate or applanate; surface varnished, 

 encrusted, sulcate, vinose, or anoderm, rarely zonate; context 

 corky to punky; tubes cylindric, stratiose; spores smooth, hyaline 

 or brown. 



A genus of some three hundred species. 



T, . . . /T \ /-111 88, 67, 78, 79 



F. igmanus (L.) Gill. 



Pileus woody, ungulate, sessile, 6-7 x 8-10 x 5-12 cm.; surface 

 smooth, encrusted, opaque, velvety to glabrous, ferruginous to 



Fig. 307. — Fomes igniarius, from maple. After Atkinson. 



fuscous, becoming rimose with age; margm obtuse, sterile, fer- 

 ruginous to hoary, tomentose; context woody, distinctly zonate, 

 ferruginous to fulvous, 2-3 cm. thick; tubes evenly stratified, 

 2-4 mm. long each season, fulvous, whitish-stuffed in age, mouths 

 circular, minute, 3-4 to a mm., edges obtuse, ferruginous to ful- 

 vous, hoary when yoimg: spores globose, smooth, hyaline, 6-7 ii; 

 spines 10-25 x 5-6 m- 



It is the cause of a white heart-rot, is one of the most widely 

 distributed forms of wound parasites and occurs on more species 

 of broad-leaf trees than any other similar fungus. Among its 

 hosts are beech, oak, apple, peach, willow, aspen, the maples, birch, 

 butternut, walnut, oak, hickory, alder. 



The first sporophores usually appear at the point of initial 



