WESTERN POLYPORES 9 



menium which is quite characteristic and rarely seen in species 

 of this genus and its near relatives. 



7. TYROMYCES PERDELICATUS Murrill 



Pileus flabelliform to subcircular, varying with its position on 

 the substratum, thin, fragile, milk-white throughout, 1-2 cm. 

 broad; surface finely tomentose to glabrous, scarcely zonate, 

 uneven, margin concolorous, thin, inflexed when dry; context 

 very thin, white, fragile; tubes minute, glistening, mouths 

 angular, subregular, edges very thin, slightly toothed, fragile; 

 spores oblong-ellipsoid, smooth, hyaline, 7 X 3 p. 



This small, snow-white species was collected several times at 

 Seattle, Washington, on fallen dead branches of conifers, and 

 was also found common at Glen Brook, Oregon. The type 

 specimens grew on Tsuga heterophylla. 



8. TYROMYCES PSEUDOTSUGAE Murrill 



Pileus imbricate-sessile, flabelliform to semicircular, 2-3 X 

 2-3 X 0.3-1 cm.; surface milk-white, subglabrous, azonate or 

 with zones faintly outlined, margin thin, concolorous, narrowly 

 sterile, entire to slightly lobed, inflexed when dry; context thin, 

 white, fragile; tubes varying greatly in length, those behind often 

 reaching nearly i cm., mouths large, irregular, edges thin, fragile, 

 toothed, collapsing, white, becoming yellowish on drying; spores 

 ovoid, smooth, hyaline, 5 X 3-5 ju. 



Known only from the original specimens collected at Seattle, 

 Washington, on a dead log of Pseudotsuga taxifolia. 



9. TYROMYCES SUBSTIPITATUS Murrill 



Pilei subcespitose, at times united above, irregularly subcircular 

 or flabelliform, depressed, milk-white throughout, 2-4 cm. broad, 

 2-3 cm. high, 2-3 mm. thick; surface glabrous, uneven, lightly 

 marked with irregular, radiating, raised lines, margin thin, con- 

 colorous, sterile, undulate or slightly lobed, slightly blackening 

 when bruised; context fleshy, fragile when dry, very thin; tubes 

 small, regular, fragile, collapsing, edges thin, toothed; spores 

 ovoid, smooth, hyaline, 4 X 2.5^; stipe erect, lateral or sub- 

 central, enlarging upward, reticulate on one side, owing to the 

 undeveloped tubes, 1-2 cm. long, 2-4 mm. thick. 



Found at Seattle, Washington, on rich soil mixed with humus, 

 but not attached to wood. The species is aberrant, partly on 



