NORTHERN POLYPORES 25 



enemies of shade trees in Europe, but it is fortunately too rare 

 as yet in this country to be dangerous. 



9. POLYPORUS UNDERWOODII Murrill 



Pileus varying from convex to deeply concave, 12-25 cm. in 

 diameter, averaging 0.5 cm. in thickness; surface obscurely 

 concentrically zonate, milk-white, pruinose, cremeous on drying, 

 the center depressed and avellaneous; margin irregularly undu- 

 late, lobed, either deflexed or recurved, very thin, not ciliate; 

 context white, fleshy, tough, 2-5 mm. thick; tubes milk-white, 

 2-3 mm. long, 5-6 to a mm., cylindric, edges thin, entire to 

 lacerate; spores ellipsoid, 6-7 X 3 /x; stipe short, central, solid, 

 woody, equal or tapering downward, smooth, pruinose, white 

 above, fuliginous below, 3 cm. long, 2-3 cm. thick. 



Occasional on dead roots of deciduous trees in Massachusetts, 

 Connecticut, and New York. 



10. POLYPORUS ELEGANS (Bull.) Fries 



Pileus flabelliform to subcircular, scarcely depressed behind, 

 convex or nearly plane, 2-6 X 3-10 X 0.2-1 cm.; surface dis- 

 tinctly radiate-striate, pruinose when young, becoming glabrous 

 and pale-ochraceous at maturity; margin thin, at first inflexed, 

 often becoming wavy or much lobed and folded with age, not 

 ciliate; context white or pallid, corky, 1-5 mm. thick; tubes pale- 

 avellaneous, 1-3 mm. long, cylindric, mouths angular to sub- 

 circular, entire, at first white, glistening, pale-umbrinous with 

 age, 4-5 to a mm., edges thin, entire ; spores oblong, 7-8 X 3-3.5 p-', 

 stipe eccentric or lateral, rarely central, woody, smooth, pallid 

 above, abruptly black and scutate below, 1-4 cm. long, 2-5 mm. 

 thick. 



Common throughout, especially northward, on fallen branches 

 and trunks of deciduous trees. 



ii. POLYPORUS FISSUS Berk. 



Pileus flabelliform to subcircular, often depressed at the disk 

 or behind, convex, very variable in size, 5-15 X 7-20 X 0.3-1 

 cm. ; surface glabrous, minutely radiate-striate, bay or fuliginous, 

 rugose on the disk; margin thin, fertile, wavy or lobed, often 

 splitting with age; context corky, pallid, 2-8 mm. thick; tubes 

 white to yellowish-brown, decurrent, 2 mm. long, cylindric, 

 slender, mouths subcircular, very minute, 6-7 to a mm., edges 

 thin, entire, becoming elongate with age; stipe eccentric, varying 

 to central or lateral, usually tapering above, fuliginous to nearly 

 black, pruinose, rugose, 2-6 cm. long, 0.5-2 cm. thick. 



