The North American species of Psathyrella.

322 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VOL. 24
6. Pleurocystidia nine-pin-shaped to fusoid-ventricose, 36-57 X 10-17 u; with
the stature of P. conopilea. 298. P. subdebilis.
6. Not as above. 7
7. Stipe 6-12 cm long. 8
7. Stipe 2-6 cm long. 9
8. Pileus cinnamon brown at first. 301a. P. gracilis var. fulva.
8. Pileus grayish to honey-brown when fresh. 301. P. gracilis var. gracilis.
9. Pleurocystidia rare to scattered and typically less than 50,L long. 299. P. atomata.
9. Pleurocystidia often 50 A long. 10
10. Spores 11-13 X 5.5-6.5 Au; stipe thinly appressed white-fibrillose (but lacking
a veil); pileus cuticle a layer of vesiculose cells 1-2 cells deep.
302. P. superiorensis.
10. Not as above. 11
11. Pileus dark vinaceous brown when young and fresh; spore apex not conspicuously
truncate; spores elliptic in face view, 12-14(-17) X 7-8 Iu. 297. P. anaglaea.
11. Pileus a medium date brown when moist; spore apex conspicuously truncate; spores
typically ovate in face view. 300. P. filamentosa.
292. Psathyrella megaspora A. H. Smith sp. nov.
Pileus 9-12 mm latus, demum planus vel umbonatus, glaber, rugulosus, pallide
alutaceus, demum vinaceus; lamellae pallidae demum atratae, confertae, angustae,
ad acierum vinaceae; stipes 4-6 cm longus, circa 1 mm crassus, glaber, pallidae,
deorsum brunneae; sporae 14-20 x 6-8 /; pleurocystidia 32-44 x 10-16 /, fusoideventricosa, acuta; fibulae adsunt; Typus. Smith 66718 (MICH); legit prope
Tahquamenon Falls State Park, Michigan.
Pileus 9-12 mm broad, convex expanding to plane with the margin wavy, or
retaining a low obtuse umbo, cinnamon-buff fresh, vinaceous and rugulose when
faded. Context very thin and delicate, odor none.
Lamellae pallid becoming blackish, close, narrow, adnate, edges pinkish in age.
Stipe 4-6 cm long, about 1 mm thick, equal, naked, pallid above and only
slightly brownish below.
Spores 14-20x 6-8 Lu, smooth, truncate from a distinct apical pore, shape in
face view narrowly ovate to nearly oblong, in profile ~ obscurely inequilateral,
color in KOH near "mummy brown" (blackish brown), in Melzer's dark bay,
wall about 0.7 i thick.
Basidia 1- to 2-spored, 10-13 j wide, very short. Brachybasidioles present.
Pleurocystidia 32-44x 10-16 u, fusoid-ventricose with acute apex, hyaline, thinwalled, smooth, cell content not distinctive. Cheilocystidia of 2 kinds: (1) like
the pleurocystidia but blunter and shorter, and (2) clavate and with yellow walls
in KOH, 9-14 x 6-10 p.
Cuticle of pileus of vesiculose hyaline cells 1-2 deep. Hyphae of trama
incrusted with rusty brown to ochraceous pigment. Clamps present.
Type locality. Tahquamenon Falls State Park, Michigan.
Habit and habitat. Scattered on wet soil.
Distribution. Michigan.
Observations. The large spores and pale buff pileus are distinctive.
293. Psathyrella praeatomata A. H. Smith, sp. nov.
Pileus 8-15 mm latus, conicus, glaber, demum campanulatus vel umbonatus,
fusco-brunneus; contextu fumoso-brunneus; lamellae subdistantes, adnatae, fuscobrunneae, in exsiccatis atrae; ad acierum vinaceae; stipes 2-5 cm longus, circa
1.5 mm crassus, pallidus, deorsum brunneus; sporae 11-14(-15) X 5.5-7 A, in