1 8 NORTHERN POLYPORES 



Hymenium smoke-colored when young, soon becoming black. i. B. adusta. 



Hymenium pallid when very young, becoming more or less blackish 

 with age. 2. B. fumosa. 



1. BjERKANDERA ADUSTA (Willd.) P. Karst. 



Pileus cespitose-imbricate, decurrent, sometimes effused, 

 conchate, fleshy-tough or corky, somewhat flexible when dry, 

 2-4 X 4-8 X 0.2-0.4 cm.; surface undulate, indistinctly zonate, 

 especially near the margin, finely tomentose or villose, isabelline 

 with slightly darker markings; margin thin, undulate, sterile, 

 pallid, usually becoming black as though scorched; context 

 fibrous-corky, white, 1-3.5 mm - thick; tubes short, I mm. or 

 less long, smoky-white to blackish within, mouths regular, 

 angular, 5-6 to a mm., smoke-colored and pruinose when young, 

 soon becoming grayish-black, edges thin, entire; spores ellipsoid- 

 allantoid, 3-5 X 1.5-2.5^1. 



Extremely common throughout on dead deciduous wood and 

 rarely on that of coniferous trees. 



2. BJERKANDERA FUMOSA (Pers.) P. Karst. 



Pileus cespitose-imbricate, fleshy-corky, firm, dimidiate, con- 

 chate, decurrent, 2-4 X 5-10 X 0.5-2 cm.; surface smooth, 

 finely tomentose, pale-isabelline, subzonate at times; margin 

 thin, concolorous, undulate, easily blackening, usually broadly 

 sterile; context fibrous-corky, somewhat zonate, white to pallid, 

 5-15 mm. thick; tubes short, 2-3 mm. long, white to discolored 

 within, mouths regular, even, circular, 4-5 to a mm., whitish to 

 smoky-isabelline and finally blackish with extreme age, edges 

 thick, entire; spores globose, 5-8 M- 



Common throughout on decayed deciduous wood and rarely 

 on coniferous wood. B. puberula (Berk. & Curt.) Murrill is not 

 sufficiently distinct. 



8. TRAMETES Fries 



Hymenophore annual, epixylous, sessile; surface anoderm, 

 white, azonate; context white, homogeneous, coriaceous to soft- 

 corky; hymenium concolorous, rigid; tubes thin-walled, mouths 

 circular to irregular; spores smooth, hyaline. 



Tubes small, 4 to a mm.; found on Robinia. I. T. robiniophila. 



Tubes large, 2 to a mm.; found on Salix. 2. T. suaveolens. 



i. TRAMETES ROBINIOPHILA Murrill 



Pileus more or less imbricate, dimidiate, convex above, plane 

 or concave below, sometimes undulate, 6-8 X 1015 X 2-4 cm.; 



