The North American species of Psathyrella.

1972]

PSATHYRELLA

205

Stipe 3-5 cm long, 1-1. 5 mm thick, equal, fragile, strigose at base, brown over
all but darker below, at first thinly fibrillose from veil remnants.
Spores 11-14x5.5-6.5 An, smooth, apex truncate from a broad apical pore,
shape in face view elliptic to nearly oblong, in profile obscurely inequilateral,
color in KOH dark cocoa-brown quickly becoming chocolate-brown to dark
chocolate, in Melzer's bay-brown, wall 0.7-1 p thick.
Basidia 4-spored, 12-13 p broad, length variable, hyaline in KOH. Pleurocystidia abundant, 48-64 x10-18 /j, fusoid-ventricose with obtuse to nearly
rounded apex or in age subacute, wall thin, smooth and hyaline, cell content not
distinctive. Cheilocystidia shorter and more subfusoid, otherwise resembling the
pleurocystidia. Pileus cuticle a layer of vesiculose cells 2-3 deep, walls pale
cinnamon in KOH when young, hyaline in age. Hyphae of subcuticular zone
rusty brown from conspicuous rusty brown pigment incrustations on the walls.
Clamp connections present.
Type locality. Colonial Point, Burt Lake, Cheboygan County, Michigan.
Habit and Habitat. Solitary to scattered on small sticks in muddy or wet soil,
July.
Distribution. Michigan.
Observations. This is a smaller species than P. gracilis, has a thin veil, darker
brown pileus and stipe, slightly smaller spores, and shorter cystidia.
Material examined. Michigan: Smith 49832, 50168, 75678 (Type).
164. Psathyrella rufogrisea A. H. Smith, sp. nov.
Pileus 10-15(-20) mm latus, late conicus vel expanso-umbonatus, floccosofibrillosus, glabrescens, castaneus; lamellae latae, confertae avellaneae demum
fusco-brunneae; stipes 3-5 cm longus, 1-1.5 mm crassus, pallidus, deorsum demum
brunneus, fibrillosus, glabrescens; sporae 9-12 x 5.5-6.5 Jt; pleurocystidia 40-60 x
10-15 A, fusoideo-ventricosa, subacuta; fibulae adsunt. Typus. Smith 23780
(MICH); legit Mt. Hood National Forest, Oregon.
var. rufogrisea
Illust. P1. 59, fig. a; Text Figs. 365-368.
Pileus 10-15 (-20) mm broad, obtuse to nearly convex when young, expanding
to broadly conic or nearly plane, umbo almost disappearing, surface at first
covered by a coating of superficial white fibrils which become aggregated into
small patches and finally disappear, "chestnut-brown" when moist, near "avellaneous" when faded, margin sometimes decorated with minute silky white patches
of veil material. Context very thin and fragile, no odor or taste noted.
Lamellae bluntly adnate, readily seceding, broad, close, in some near subdistant at maturity, avellaneous then chocolate-color, edges whitish.
Stipe 3-5 cm long, 1-1.5 mm thick, equal or slightly enlarged downward,
fragile, tubular, pallid ("tilleul buff") or slightly darker toward the avellaneous
base or in age base more brownish, surface covered by scattered white fibrils over
lower half.
Spores 9-12 x 5.5-6.5,, smooth, apical pore distinct and apex somewhat
truncate (under low oil immersion), shape in face view broadly elliptic to slightly
ovate, in profile subelliptic to obscurely inequilateral, color in KOH dark bister
slowly going to "mummy brown" and finally dark chocolate-color, in Melzer's
dark reddish tawny, wall about 0.5 / thick.
Basidia 4-spored, 18-28 x 9-12 u, subcapitate to clavate. Brachybasidioles not