34 NORTHERN POLYPORES 



somewhat irregular, 3-4 to a mm., edges very thin, lacerate, 

 sulphur-yellow, the color fairly permanent in dried specimens; 

 spores ovoid, smooth or finely papillate, 6-8 X 3-5 M- 



Common throughout on living trunks of all our deciduous 

 and evergreen trees, causing a very serious heart-rot. It is one 

 of the best edible fungi. 



20. CERRENELLA Murrill 



Hymenophore thin, effused-reflexed, annual, epixylous; surface 

 brown, zonate, anoderm, margin thin; context thin, coriaceous, 

 brown; hymenium at first poroid, very soon becoming irpiciform, 

 the teeth irregular and compressed; spores smooth, hyaline. 



i. CERRENELLA FARINACEA (Fries) Murrill 



Pileus very thin, soft, flexible, coriaceous, entirely resupinate 

 or effused-reflexed, the reflexed portion dimidiate, imbricate, 

 laterally connate, o-i X 1-5 X o.i cm.; surface finely con- 

 centrically striate, tomentose, umbrinous-chestnut; margin very 

 thin, undulate to lobed, sterile; context membranous, concolor- 

 ous, papery-thin; tubes short, I mm. or less, irregular, 2-3 to a 

 mm., edges thin, fimbriate to lacerate, dentate, separated at a 

 very young stage forming an irpiciform hymenium, yellowish- 

 green to olive and finally cinereous and farinaceous; spores 

 6-7 X 2.5 p. 



Occasional on decaying branches of oak and other hardwood 

 trees in Iowa, Ohio, and southward. 



21. CORIOLOPSIS Murrill 



Hymenophore thin, flexible or rigid, annual, epixylous, sessile, 

 dimidiate, often largely resupinate; surface light-brown to bay- 

 black, zonate, anoderm, rarely encrusted with age, hairy; margin 

 thin; context thin, coriaceous to woody, isabelline to purplish- 

 umbrinous, rarely almost white; hymenium concolorous; tubes 

 small, regular, thin-walled, entire; spores smooth, hyaline. 



i. CORIOLOPSIS RIGIDA (Berk. & Mont.) Murrill 



Pileus thin, coriaceous, flexible to rigid, effused-reflexed, 

 imbricate, laterally connate, the reflexed portion flabelliform, 

 applanate or conchate, 0.5-3 X 3-6 X 0.1-0.2 cm.; surface 

 spuriously zoned, sometimes zonate behind, concentrically fur- 

 rowed at times, hirsute to hispid, nearly white to isabelline; 

 margin very thin, pallid, undulate to lobed; context pallid to 



