NORTHERN POLYPORES 5 



edges uneven, soon splitting into teeth, which are compressed, 

 pointed, fimbriate, dentate to incised; spores cylindric, slightly 

 curved, smooth, 6-7 X 2-3 fj.. 



Extremely common throughout on dead branches and trunks 

 of deciduous trees. 



2. PORONIDULUS Murrill 



Hymenophore annual, tough, sessile, epixylous, at first sterile 

 and cup-like, the fertile portion developing from the sterile; 

 context white, fibrous; tubes short, thin-walled, mouths poly- 

 gonal; spores ellipsoid, smooth, hyaline. 



i. PORONIDULUS CONCHIFER (Schw.) Murrill 



Pileus thin, coriaceous, dimidiate to flabelliform, usually 

 narrowly attached, conchate, springing from a sterile, cup-like 

 structure, which usually appears on the mature sporophore near 

 the base, 1.5-2 X 2-4 X 0.1-0.2 cm.; surface white to isabelline, 

 with pale-latericeous zones, finely tomentose to glabrous, the 

 sterile portion avellaneous, with narrow, black, concentric lines; 

 margin thin, concolorous, undulate; context very thin, mem- 

 branous, less than I mm. in thickness; tubes short, about I mm. 

 long, thin-walled, white, mouths angular, irregular, 3 to a mm., 

 edges thin, uneven, dentate. 



Very common throughout on dead elm branches. 



3. CORIOLUS Quel. 



Hymenophore annual, epixylous, sessile, zonate, anoderm, 

 hairy or glabrous; context thin, white, flexible, fibrous, leathery; 

 tubes thin-walled, white, at length splitting into irpiciform teeth 

 in several species, mouths polygonal or irregular; spores smooth, 

 hyaline. 



Tubes more or less entire, at least until the sporophore is 



quite old. 



Surface of pileus wholly or partly glabrous when 

 mature or clothed only with inconspicuous hairs. 

 Pileus not entirely glabrous at maturity. 



Pileus marked at maturity with glabrous zones 

 of a different color from the rest of the 

 surface. 



Glabrous zones large, numerous, conspicu- 

 ously and variously colored. i. C. versicolar. 

 Glabrous zones small and comparatively 

 inconspicuous. 2. C. pubescens. 



