The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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seceding, broad (about 4 mm), "drab-gray" at maturity, the edges whitish and
scarcely fimbriate.
Stipe 4-6 cm long, 1.5-3 mm thick, equal, strict, fragile, hollow, whitish, becoming dingy brownish at base, with thin white fibrillose flecks from the remains of
a thin veil, glabrescent, apex pruinose.
Spores 6-7.5 x 3.2-3.8(-4) a, smooth, apical pore evident and apex somewhat
truncate, shape in face view oblong to narrowly ovate, in profile somewhat beanshaped to obscurely inequilateral, color in KOH pale cocoa-color when first
revived, finally a medium chocolate-brown, reddish brown in water mounts when
fresh, in Melzer's tawny-red, wall about 0.2 pj thick.
Basidia 4-spored, 14-20 x6-8 pt, clavate, hyaline in KOH. Pleurocystidia
abundant, 42-60 x 8-12 j, subcylindric to somewhat fusoid-ventricose, neck evenly
tapered to an obtuse or subacute apex, smooth, hyaline (in KOH), thin-walled,
cell content not distinctive in KOH or Melzer's. Caulocystidia very rare, resembling the pleurocystidia. Cheilocystidia of two types, saccate and 17-26 x 10-15 M
or fusoid-ventricose to subcylindric and 34-54 x 8-13 I,, both types hyaline, smooth
and thin-walled.
Gill trama regular, the hyphae somewhat interwoven and with enlarged cells,
pallid to reddish brown in KOH. Pileus having a cuticle of vesiculose but somewhat elongated hyaline cells 1-2 cells deep. The hyphae of the context pale
cinnamon in KOH in the subcuticular region. Clamps present.
Type locality. Lake Crescent, Clallam County, Washington.
Habit and habitat. Scattered under brush on humus and debris in a mixed
conifer and alder stand.
Distribution. Washington.
Observations. Since Fries consistently noted P. obtusata as occurring on wood
(especially oak), and since I regard the difference between humus dwellers and
lignicolous species to be important, I must insist on the typification of P. obtusata
in accordance with Fries' notations. This means that the current concepts of the
species in Europe will have to be abandoned as I am abandoning my (1941)
concept based upon them. Drosophila pygmea Quel. has the spores of this species
but has no veil and its pleurocystidia are short (under 40 Pu long).
383. Psathyrella rubiginosa A. H. Smith, sp. nov.
Pileus 10-20 mm latus, late convexus, glaber, rufo-fulvus; contextu rufofulvus; lamellae latae, confertae, subdistantes, brunneolae, fulvae demum fumosofulvae; stipes 1-5 cm longus, 1-2 mm crassus, pallidus demum brunneolus, glaber;
velum nullum; sporae 7-8x4-4.5 ju; pleurocystidia 28-48 x 9-14 /, obtuse
fusoideo-ventricosa; fibulae adsunt. Typus. Smith 34616 (MICH); legit prope
Laramie, Wyoming.
Illust. P1. 87, fig. b; Text Figs. 854-856.
Pileus 10-20 mm broad, obtuse expanding to convex or broadly convex, surface
glabrous, moist, hygrophanous, no evidence of a veil, color "russet" to "Mars
brown" or "cinnamon-brown" (dark rusty brown becoming paler), fading to tan
or pale dingy tan, no pinkish tint evident in old faded pilei. Context very thin and
delicate, concolorous with surface, odor and taste not distinctive.
Lamellae broad, adnate, close at first, subdistant at maturity, pale brown
before becoming colored by spores and then dark rusty brown finally clouded with
chocolate-color, the reddish component evident on dried lamellae (color near
"Natal brown"), edges even, not pinkish in age.