52 NORTHERN POLYPORES 



ferruginous, floccose and rigid; pilei very numerous, cespitose- 

 branched, closely imbricate, occupying the periphery of the 

 mass; pileus corky, rigid, conchate, usually plicate, 1-3 X 0.5- 

 0.8 cm.; surface radiately sulcate, slightly zonate, purplish- 

 fuscous, pulverulent to glabrous, slightly resinous in appearance, 

 encrusted, grayish-black with age; margin fulvous, pulverulent, 

 undulate or lobed, subacute, deflexed, sterile on the perpendicular 

 portion, which is from 2 to 3 mm. long; context floccose, fer- 

 ruginous, 2-5 mm. thick; tubes 2 mm. long, grayish-umbrinous, 

 mouths circular, whitish-pulverulent to castaneous, fuliginous 

 with age, edges thick, entire; spores globose or ovoid, smooth, fer- 

 ruginous, 4/z; cystidia ovoid, hyaline, rather abundant, 7 X 4 n. 

 Occasional on dead trunks of oak, maple, and beech from 

 Pennsylvania to Iowa and southward. Sometimes known as 

 " sweet-knot," but the odor has also been described as disagree- 

 able or entirely wanting. Polyporus botryoides LeV. is probably 

 not distinct. 



36. ELFVINGIELLA Murrill, gen. nov. 



Hymenophore large, epixylous, sessile, applanate or ungulate; 

 surface sulcate, horny-encrusted; context brown, punky; tubes 

 brown, cylindric, stratose, thick- walled ; spores smooth, hyaline 

 or subhyaline. 



Type species, Elfvingia fomentaria (L.) Murrill. 



i. ELFVINGIELLA FOMENTARIA (L.) Murrill, comb. nov. 



Pileus hard, ungulate, concave below, 7-9 X 8-10 X 3-10 cm.; 

 surface finely tomentose to glabrous, isabelline to avellaneous and 

 finally black and shining with age, zonate, sulcate, horny- 

 encrusted; margin obtuse, velvety, isabelline to fulvous; context 

 punky, ferruginous to fulvous, conidia-bearing, 3-5 mm. thick; 

 tubes indistinctly stratified, not separated by layers of context, 

 3-5 mm. long each season, avellaneous to umbrinous within, 

 mouths circular, whitish -stuffed when young, 3-4 to a mm., 

 edges obtuse, entire, grayish-white to avellaneous, turning dark 

 when bruised; spores globose, smooth, hyaline or nearly so, 

 3-4 M- 



Common throughout on trunks of birch and beech, and 

 occasionally on maple and a few other deciduous trees, causing 

 serious decay. The punky substance of the sporophore was 

 formerly used in tinder-boxes, and is still used as an absorbent 

 in surgery and for the manufacture of various ornamental and 

 useful articles. 



