12 NORTHERN POLYPORES 



3. TYROMYCES SPRAGUEI (Berk. & Curt.) Murrill 



Pileus subimbricate, dimidiate or flabelliform, broadly sessile 

 or attenuate behind, convex, fleshy- tough and watery to rigid 

 and fragile when dry, 4-7 X 5-10 X 1-2 cm.; surface at first 

 milk-white, finely tomentose to glabrous, slightly tuberculose, 

 azonate, sodden, containing depressions filled with exuded water, 

 becoming discolored and roughened and often decaying, espe- 

 cially in damp weather, with a strong and disagreeable odor; 

 margin undulate or slightly lobed, acute, usually discolored, 

 sometimes smoky-black, inflexed when dry ; context white, zonate, 

 cheesy when fresh, rigid and somewhat fragile when dry; tubes 

 small, white to yellowish within, 3-8 mm. long, mouths some- 

 what uneven, angular, 3-4 to a mm., edges white to yellowish, 

 thin, entire; spores ellipsoid, 6 X 4 ju. 



Common throughout on dead stumps and trunks of chestnut 

 and oak. 



4. TYROMYCES TILIOPHILA Murrill 



Pileus large, convex above, concave below, cheesy when fresh, 

 firm and fragile when dry, attached by an attenuate base, 

 dimidiate to flabelliform, 8 X 12 X 1-1.5 cm.; surface radiate- 

 rugose, slightly plicate, tubercular, subglabrous, white to 

 ochraceous, marked with pale-latericeous zones; margin thick, 

 fertile, concolorous, undulate; context homogeneous, white, 

 cheesy to fragile, about I cm. thick; tubes nearly I cm. long, 

 white to slightly yellowish, very fragile when dry, collapsing and 

 wearing away with age, mouths minute, 5 to a mm., subcircular, 

 white to cremeous, slightly discolored with age, edges thin, 

 friable, fimbriate-dentate. 



Found once on Tilia americana at Ottawa, Canada. 



5. TYROMYCES SEMISUPINUS (Berk. & Curt.) Murrill 



Pileus imbricate-cespitose, thin, rigid when dry, flabelliform, 

 narrowly attached, sometimes with a short process resembling a 

 stipe, 0.5-1 X 0.5-0.8 X 0.05-0.1 cm.; surface white to flavous, 

 partially dull-latericeous, cartilaginous, glabrous or ornamented 

 with a few abnormal hydnoid processes, subzonate; margin very 

 thin, lobed, inflexed when dry; context very thin, white, horny 

 and fragile when dry; tubes short, minute, white, 2-3 mm. long, 

 mouths angular, 4 to a mm., edges thin, dentate. 



Occasional in New England, Pennsylvania, and New Jersey 

 on dead trunks of maple, alder, and other deciduous trees. 



