io WESTERN POLYPORES 



account of its habit of growing upward from the ground, and 

 might be classed with the stipitate forms of the polypores. It is 

 closely related, however, to Tyromyces semisupinus , and may as 

 well be placed in this genus as in any other. 



5. SPONGIPELLIS Pat. 



Hymenophore annual, epixylous, sessile, dimidiate, simple or 

 imbricate, rather large; surface white, anoderm, sodden and 

 bibulous; context white, duplex, spongy above, firm below; 

 hymenium concolorous, tubes thin-walled; spores smooth, 

 hyaline. 



Pileus 10-15 cm. broad; tubes very large, 1-2 mm. broad. i. S. unicolor. 



Pileus reaching 6 cm. broad; tubes very much smaller. 2. 5. sensibilis. 



i. SPONGIPELLIS UNICOLOR (Schw.) Murrill 



Pileus somewhat imbricate, large and spongy, at length 

 indurate, dimidiate, often ungulate, 5-7 X 10-15 X 3-5 cm.; 

 surface spongy-tomentose, hirtose, azonate, smooth, sordid- 

 white to isabelline or fulvous; margin very thick and rounded, 

 sterile, entire, concolorous; context spongy-fibrous, white, in- 

 durate with age, especially below, 1-2 cm. thick; tubes very 

 long, 2-3 cm., white to isabelline within, mouths large, irregular, 

 often sinuous, 1-2 mm. broad, edges thin, fimbriate-dentate to 

 slightly lacerate, white to isabelline, at length bay and resinous 

 in appearance; spores globose, 6-8 /*. 



Occasional on diseased trunks of deciduous trees in Oregon. 



2. SPONGIPELLIS SENSIBILIS Murrill 



Pileus flabelliform-conchate, narrowly attached, tough, very 

 juicy, white throughout, changing color very quickly when 

 bruised or on drying, about 3-4 cm. long, 6 cm. broad, and 1.5-2 

 cm. thick behind; surface spongy-tomentose, azonate, somewhat 

 uneven, changing at once to melleous when bruised and at length 

 to bay, margin entire, regular, very sensitive to handling, thin, 

 scarcely deflexed on drying; context duplex, white, thick, axonate 

 and friable when dry above, zonate and woody below, changing 

 color like the surface when bruised; tubes about equaling the 

 thickness of the context, small, at first very white and glistening, 

 changing quickly to bay when bruised, mouths circular, even, 

 slightly angular, friable and easily corroded on drying, 4-5 to a 

 mm., edges very thin, long-toothed, becoming lacerate at times; 

 spores ovoid, smooth, hyaline, 5 X 3 /*. 



