48 NORTHERN POLYPORES 



32. PYROPOLYPORUS Murrill 



Hymenophore large, perennial, epixylous, sessile, ungulate or 

 applanate; surface sulcate, usually anoderm and often rough or 

 rimose; context woody or punky, brown; tubes brown, cylindric, 

 stratose, usually thick-walled; spores smooth, hyaline. 



Pileus thick, ungulate; not found on Prunus. 



Context fulvous, opaque. I. P. igniarius. 



Context melleous, lustrous. 2. P. Bakeri. 



Pileus thick, terraced, imbricate or semiresupinate; margin 



making an obtuse angle; found on Prunus. 3. P. fulvus. 



Pileus thin, conchate, largely resupinate. 4. P. conchatus. 



i. PYROPOLYPORUS IGNIARIUS (L.) Murrill 



Pileus woody, ungulate, sessile, 6-7 X 8-10 X 5-12 cm.; 

 surface smooth, encrusted, opaque, velvety to glabrous, fer- 

 ruginous to fuscous, becoming black and rimose with age; 

 margin obtuse, sterile, ferruginous to hoary, tomentose; context 

 woody, distinctly zonate, ferruginous to fulvous, 2-3 cm. thick; 

 tubes evenly stratified, 2-4 mm. long each season, fulvous, 

 whitish-stuffed in age, mouths circular, minute, 3-4 to a mm., 

 edges obtuse, ferruginous to fulvous, hoary when young; spores 

 globose, smooth, hyaline, 6-7 /*; cystidia 10-25 X 5-6 /*. 



Common throughout on living trunks of various deciduous 

 trees, causing a very serious heart-rot. Formerly a source of 



tinder. 



2. PYROPOLYPORUS BAKERI Murrill 



Pileus compressed-ungulate to applanate, dimidiate, slightly 

 decurrent, 4-10 X 8-20 X 3-5 cm.; surface smooth, anoderm, 

 becoming glabrous, 2-3 times deeply sulcate, isabelline to gray 

 or umbrinous; margin very broad and rounded, ferruginous, 

 finely tomentose, perfectly smooth ; context woody, dark-luteous, 

 somewhat shining, 1.5-2 cm. thick; tubes distinctly stratified, 

 5-7 mm. long each season, avellaneous to fulvous within, mouths 

 circular, 4 to a mm., edges obtuse, entire, light-yellowish to 

 fuliginous; spores globose, smooth, hyaline, 5 /j.. 



Occasional on oak and black birch trunks in Wisconsin, Mis- 

 souri, and westward. 



3. PYROPOLYPORUS FULVUS (Scop.) Murrill 



Pileus woody, triquetrous, rarely ungulate, thick and broadly 

 attached behind, 1-3 X 5-7 X 3-8 cm.; surface smooth, very 

 slightly sulcate, velvety, ferruginous, becoming horny and 



