4S THE CHICAGO ACADEMY OF SCIENCES 



On trunk of Acer N eg undo, Wheaton. October, 1896. Pileus 

 elliptical, 27 x 20 cm. in the largest specimen. On living trunks 

 of Ulmus. River Forest and Bowmanville. Often 7 to 20 meters 

 from the ground. 



Pleurotus seroiinus Fr. 



Pileus fleshy, compact, convex or nearly plane, viscid when 

 young and moist, dimidiate, reniform or suborbicular, solitary or 

 cespitose and imbricated, variously colored, dingy-yellow, red- 

 dish-brown, greenish-brown or olivaceous, the margin at first 

 involute. 



Lamellae close, determinate, whitish or yellowish. 



Stem very short, lateral, thick, yellowish beneath and minutely 

 tomentose or squamulose with blackish points. 



Spores elliptical, 5 x 2.5 /x. Pileus 2.5 to 7.5 cm. broad. 



Reported from woods at Bowmanville by Bertolet, Harper 

 and Pepoon. Autumn. 



Pleurotus dryinus Fr. 



Pileus white or buff, convex or expanded, more or less depressed 

 in the center, margin floccose, becoming floccose-scaly. 



Lamellae white becoming tinged with yellow in age, decurrent 

 in lines down the stem, not crowded. 



Stem varying from nearly central to definitely lateral, smooth, 

 white, tough, fibrous; veil floccose. 



Pileus 5 to 10 cm. broad; stem 2 to 12 cm. long, 1 to 2 cm. 

 thick. 



Knot-hole in a log, River Forest. October, 1903. 



The upper portion of the stem is pruinose between the decur- 

 rent striae of the lamellae. Lamellae shining-white, not anastom- 

 osing behind. I find no record of the size of the spores of this 

 species. Cooke's figure, Illust. PI. 226, shows them to be narrowly 

 oblong. In our plant they are oblong, 14 x 4 u. The pileus is 

 5 to 8 cm. broad; the stem 5 cm. long, 1 to 2 cm. thick. 



Pleurotus salignus Schw. 



Pileus fleshy, compact, spongy, somewhat dimidiate, horizon- 

 tal, at first pulvinate, even, afterwards the disk depressed, some- 

 what strigose, fuliginous-cinereous, sometimes ochraceous. 



Lamellae decurrent, some of them branched, eroded, distinct 

 at the base, subconcolorous with the pileus. 



Stem short, tomentose. 



On decaying wood of Ulmus americana, Wheaton. October. 

 Pileus 7.5 to 12.5 cm. broad, both it and the lamellae tougher 

 than those of P. ostreatus. Lamellae pallid, at length ochraceous, 

 decurrent, not anastomosing behind. The species grows slowly, 

 lasting three or four weeks. Spores abundant, pure white, 9 to 

 13 x 5 to 6 x. 



