The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Lamellae adnate but soon seceding, close, 24-35 reach the stipe, narrow but
becoming broad (3-7 mm), "tilleul-buff" (pallid) when young, "wood brown" to
"hair brown" at maturity, in age near "benzo brown" (lacking a red component),
edges even and whitish.
Stipe 5-8 cm long, 3-8 mm thick, equal or narrowed slightly toward the apex,
hollow, white, fragile, surface white-fibrillose or fibrillose-scaly, appressed
fibrillose toward the more or less striate apex.
Spores in deposit "hair brown" (grayish brown); 6-8 x 3.5-4.5 Ia, smooth, apex
truncate from an inconspicuous apical pore, shape in face view oblong to elliptic
or narrowly ovate, in profile somewhat inequilateral to obscurely bean-shaped,
color in KOH at first dark cocoa-color, soon dark chocolate-brown, in Melzer's
tawny reddish, wall about 0.2, thick.
Basidia 4-spored, 15-20x 5-8 It, hyaline, clavate. Pleurocystidia very abundant, 42-58(-70) x9-14(-17) p, fusoid-ventricose, the apex obtuse to subacute
and near the apex often with adhering debris as revived in KOH, wall hyaline
and thin or rarely very slightly thickened and refractive in KOH, cell content not
distinctive in KOH or in Melzer's. Cheilocystidia numerous, 28-40x9-15 A,
saccate, somewhat clavate, fusoid-ventricose with subacute apex, or the apex at
times subcapitate and the wall thickened very slightly and refractive in KOH,
cell content not distinctive. Caulocystidia mostly some variation of clavate to
broadly fusoid-ventricose, up to 25 M wide and length variable, some vesiculose,
cell content not distinctive.
Pileus with a cuticle of vesiculose cells 1-2 deep and most vertically arranged
(clavate to inflated-pedicellate), walls smooth and hyaline or colored in the
pedicel, content not distinctive in KOH or in Melzer's. Hyphae of the context
vinaceous-brown in KOH but fading, the hyphae finely incrusted to smooth.
Clamp connections present. No distinctive reactions noted for any tissue mounted
in Melzer's.
Type locality. Jackson Guard Station, Hoh River, Olympic National Park,
Washington.
Habit and habitat. On wood and lignicolous debris of cottonwood, May.
Distribution. Idaho, Michigan and Washington.
Observations. This is probably one of the fungi to pass under the name of
"Hypholoma appendiculatum" in this country. P. xanthocystis Orton is close to
this species.
Material examined. Idaho: Smith 70170, 71245. Michigan: Imshaug 4901;
Smith 22187, 23395, 25400, 32705, 33861, 77554. Washington: Imshaug 1142;
Smith 13178, 13241, 13518, 13603, 14089, 14143 (Type) 14606, 14706, 16308,
28833, 29357, 29997, 30800, 39864, 39867, 48480, 48595, Aug. 1948.
122a. Psathyrella iterata var. ochraceispora A. H. Smith, var. nov.
A typo differt: sporae 7-9(-10) x4-4.5(8-10x2.5-3) I, in "KOH" pallide
fulvae; lamellae latae; velum copiosum. Typus. Smith 33-1130 (MICH); legit
prope Fowlerville, Michigan.
Illust. Text Figs. 281-283.
Pileus 2-5.5 cm broad, obtuse to convex, expanding to broadly convex, surface
moist and glabrous except for veil remnants on the margin, margin conspicuously
appendiculate, hygrophanous, color "cinnamon-brown" to "Mars brown" fading
to avellaneous or ochraceous-buff, even to somewhat radially rugulose and margin