232 
THIRTEENTH REPORT. 
26. Stem central, chestnut-colored; pileus white; tubes minute: 
Polyporus albiceps PK. 
20. Stem lateral, white; pileus white; tubes angular, glistening: 
Polyporus humilis PK. 
27. Flesh white or whitish: (28) 
27. Flesh brown, reddish or yellow (47) 
28. Pores grayish-ashy, bluish or blackish in age (29) 
28. Pores not ashy in age: , (32) 
29. Pileus soft spongy when fresh, tomentose, friable when dry; spores 
blue to slate-color in mass : Polyporus caesius Fr. 
(Tyromyces caesius). 
29. Pileus corky, glabrous or nearly so; spores white in mass : (30) 
30. Very fragrant when fresh; pileus 5-12 cm. broad, margin whitish; 
on Willow, etc. : Polyporus suaveolens Fr. 
(Trametes suaveolens). 
30. Not fragrant; margin of pileus becoming black in age or when 
bruised; caespitose, fruit-body rather large: (31) 
31. Pileus 5-20 mm. thick, smoky-colored, shelving, imbricate; tubes 2-3 
mm. long; pores whitish at times: Polyporus fumosus Fr. 
( Bj erkandera f urnosa ) . 
31. Pileus thinner, 2-4 mm. thick, effuso-reflexed, often imbricate; tubes 
1 mm. or less, long: Polyporus adustus Fr. 
(Bjerkandera adusta). 
32. Surface of pileus distinctly hairy-tomentose and spongy, mostly 
white; rather large: (33) 
32. Surface of pileus glabrous or nearly so: (36) 
33. Flesh zonate, thin, only .5 to 1 cm. thick, rigid and brittle when 
dry ; every part white or whitish: Polyporus galactin-us Berk. 
(Spongipellis galactinus). 
33. Flesh not zonate, pileus 2 to 5 cm. thick, not very brittle when 
dry : (34) 
34. On trunks of conifers; parasitic; fruit-body white or tinged yellow- 
ish : Polyporus borealis Fr. 
(Spongipellis borealis). 
34. Not known on conifers: (35) 
35. Tubes large, 1 mm. in diam. ; pileus large, 10-15 cm. wide, spongy 
when fresh, often ungulate, pale tan to cinnamon; on oak and 
maple: Polyporus unicolor Seine. 
(Spongipellis unicolor). 
35. Tubes much smaller; pileus whitish to cream color or pale tan; 
flesh soft, spongy-fibrous. On beech : Polyporus occidentalis Muir. 
(Spongipellis occidentalis). 
