io NORTHERN POLYPORES 



X 0.2-0.5 cm. ; surface white or pale-wood-colored, finely tomen- 

 tose to glabrous, subzonate, smooth or broadly radiately fur- 

 rowed; margin thin or tumid, entire to undulate; context white, 

 1-2 mm. thick, soft-corky; tubes white, 2-3 mm. long, mouths 

 angular, uneven, irregular, sometimes slightly sinuous, 1-2 to a 

 mm., edges thin, undulate to dentate, white; spores oblong, 

 12 X 5 it. 



Common throughout on structural timber and other dead 

 wood, especially that of deciduous trees. 



2. CORIOLELLUS SERiALis (Fries) Murrill 



Pileus corky to woody, extensively effused, resupinate or 

 shortly reflexed, seriately elongate, laterally connate, the reflexed 

 portion very narrow, o-i X 1-1.5 X 0.3-0.5 cm. ; surface uneven, 

 subzonate, appressed-tomentose to strigose, hoary-fulvous to 

 latericeous-fulvous; margin thick, pallid, undulate to very 

 uneven; context white, fibrous, membranous, less than I mm. 

 thick; tubes slender, white, very variable in size and shape, 

 2-8 mm. long, mouths circular to angular or irregular, pure- 

 white, becoming pale-yellowish-brown at times on drying, about 

 3 to a mm., edges rather thick, firm, entire, becoming thinner 

 and dentate; spores oblong, 6-8 X 2.5-3 M- 



Rather common throughout on dead coniferous and deciduous 

 wood. 



5. TYROMYCES P. Karst. 



Hymenophore annual, epixylous, sessile, anoderm, azonate, 

 glabrous or nearly so; context white, fibrous, fleshy to fleshy- 

 tough, rigid and friable when dry; tubes thin-walled, white or 

 yellowish, mouths polygonal; spores smooth, hyaline. 



Pileus large, 8 cm. or more in diameter. 

 Tubes less than 5 cm. long. 



Surface of pileus marked with rounded depressed 



spots. I. T. guttulatus. 



Surface of pileus not guttulate; tubes fragile, lacerate. 2. T. obductus. 

 Tubes more than 5 cm. long. 



Surface sodden, rough, white, becoming blackish, 



especially at the margin. 3. T. Spraguei. 



Surface tuberculose, ochraceous, not becoming 



blackish. 4. T. tiliophila. 



Pileus small, rarely exceeding 5 cm. in diameter. 



Pileus resinous or cartilaginous in appearance. 5. T. semisupinus. 



Pileus neither resinous nor cartilaginous. 



Tubes large, irregular, lacerate, 1-2 to a mm. 6. T. undosus. 



