42 THE CHICAGO ACADEMY OF SCIENCES . 



Stem equal, hollow, livid or pallid with a grayish or whitish 

 floeeose pruinosity. 



Spores elliptical, hyaline. 7 to S x 4 /j.. Pileus 12 to 15 mm. 

 broad; stem 2.5 to 6 cm. long. 2 to 4 mm. thick. 



On the ground among dead leaves in woods. Glen Ellyn. 

 August. The pileus when moist is livid-blackish, fading to livid- 

 gray at the margin. The margin is not at all striatulate in our 

 plants: the spores white (not hyaline), oblong, blunt-pointed, 

 6 to 7x3 u.: the lamellae are rounded behind; the stem is livid 

 without and within, clothed upwards with a whitish pruinosity 

 which is easily removed. If additional material shall show these 

 variations to be constant, the plant may be worthy of separation 

 as a varietv. 



MYCENA. 



Stem fistulose, cartilaginous: pileus somewhat membranaceous, 

 more or less striate, the margin at first straight and pressed 

 parallel to the stem: lamellae not decurrent (or only uncinate by 

 a small tooth). 



Plants terrestrial or epixylous. Spores white. 



Plant tough, inodorous, persistent 1 



1. Lamellae united behind in a collar M . rugosa. 



1 . Lamellae not united behind M. galericulata. 



2. Plant fragile, pileus striate 3 



3. With an alkaline odor M. (deal 



3. "Without odor M. tenuis. 



4. Plant bright colored 5 



5. Exuding a red juice when broken .1/. haematopa. 



•"). Juiceless 6 



6. Pileus bright orange-red. stem yellow. . M. acicvla. 

 6. Pileus and stem pinkish or violaceous. . .-V. puru. 



7. Plant viscid 8 



Pileus grayish-yellow .V. cpi]>terygia. 



8. Plant bright orange If. Leaiana. 



'.'. Plant very small, stem inserted at base . . . M. corticola. 



Mycena rugosa Fr. 



Pileus cinereous but becoming pale very tough, slightly 

 fleshy at the disk, otherwise membranaceous, campanulate then 

 expanded, at length rather plane, unequal with elevated wrinkles, 

 dry, striate at the margin. 



Lamellae arcuate-adnate with a decurrent tooth, united be- 

 hind in a collar, somewhat distant, connected by vein-, broad, 

 ventricose, white then gray. 



-tern commonly short, remarkably cartilaginous, fistulose, 

 rigid, tough, straight, at length compressed, even, smooth, pallid, 

 with a short, oblique, strigose root. 



On rotten stumps, Glen Ellyn and Winfield, September and 



October. The plant so referred is much tougher throughout than 

 .V. galericulata; the pileus is at first conic-campanulate then ex- 

 panded, darker at the disk, sometimes obtuse, oftener with a 



