168 SECTION HYGROCYBE 



finally dark grayish brown to nearly blackish, moist or soon dry, at 

 length fibrillose-squamulose, margin even, splitting readily. Context 

 thin, brittle, pale to dark brownish gray, unchanging; odor nitrous, taste 

 acidulous. 



Lamellae emarginate, whitish, darkening somewhat in age, at times 

 yellowish with a grayish tint, subdistant, broad ( up to 10 mm ) , inter- 

 venose, alternating long and short, edges even. 



Stipe 4-10 cm long, 2-10 mm thick, pale brownish at first, dark 

 grayish in age, fragile, terete to compressed, glabrous, somewhat longi- 

 tudinally striate, equal or slightly ventricose downward, base often 

 white and pointed, hollow. 



Spores 7.5-10 X 4.5-6 /x, subovoid to ellipsoid, smooth, white in 

 mass, pale yellow in Melzer's reagent. Basidia 4-spored, 32-43 X 6-9 /a, 

 mostly 4-spored, a few 2-spored. Pleurocystidia and cheilocystidia not 

 differentiated. Gill trama subparallel, hyphae 7-25 fx broad, yellowish 

 in Melzer's reagent. Cuticle of non-gelatinous, repent or more or less 

 erect hyphae, 4-12 ^ broad, which are brownish, the terminal elements 

 with more or less rounded apices and cystidioid. No hypodermium. 

 Pileus trama of radial, subparallel hyphae. Clamp connections on the 

 cuticular hyphae. 



Habit, Habitat, and Distbibution — Gregarious to scattered, on 

 soil in deciduous or coniferous woods, North Carolina, Tennessee, 

 Maine, Massachusetts, Michigan, and Canada, June-August. 



Fig. 49. H. nitratus 



