The North American species of Psathyrella.

1972]

PSATHYRELLA

401

377. Psathyrella mazamensis A. H. Smith, sp. nov.
Pileus 8-12 mm latus, late convexus, glaber, subspadiceus; lamellae confertae
latae, ventricosae, violaceo-fuscae; stipes circa 1 cm longus, filiformis pallidus
glaber, deorsum sparse fibrillosus; sporae 8-9x4-4.5 [/; pleurocystidia 34-52 X
5-10 /, subcylindrica vel anguste fusoideo-ventricosa acuta vel subacuta; fibulae
adsunt. Typus. Smith 31360 (MICH); legit prope Longmire, Mt. Rainier National
Park, Washington.
Illust. Text Figs. 766-768.
Pileus 8-12 mm broad, convex to broadly convex, glabrous except for a few
indistinct marginal fibrils, moist and hygrophanous, grayish over marginal area
(all with mature spores); disc dingy "buckthorn brown" (fairly dark honey
brown), fading to grayish over the margin but drying dull brown. Context very
thin and soft, odor and taste not recorded.
Lamellae close, broad, ventricose, horizontal and depressed-adnate, near
"benzo brown" at maturity and when dried near fuscous but retaining a slight
tinge of cocoa-color.
Stipe about 1 cm long, less than 1 mm thick, sunken in the soil and with debris
adhering around the base but no true pseudorhiza present, pallid, glabrous at
maturity, at first with scattered fibrils.
Spores 8-9x4-4.5,u, smooth, apical pore distinct but apex only obscurely
truncate, shape in face view narrowly elliptic to oblong, rarely narrowly ovate,
in profile suboblong to obscurely inequilateral, color in KOH dark cocoa-color
slowly clouded to chocolate-gray, in Melzer's reddish tawny to pale bay, wall
about 0.3,u thick.
Basidia 4-spored, clavate, hyaline in KOH 18-24x6.5-8,u. Pleurocystidia
scattered, 34-52 x 5-10 I,, subcylindric to narrowly subfusoid, the elongated neck
flexuous (3.5-5 / wide), apex acute to subacute, walls slightly thickened in the base
in some, hyaline and smooth in KOH. Cheilocystidia similar to pleurocystidia
or clavate to saccate and 7-12 J wide, both types intermingled, in the clavate to
saccate type the walls pallid to tinged cinnamon as revived in KOH.
Pileus trama tinged cinnamon in KOH but fading on standing and in thin
sections nearly hyaline. Cuticle of pileus a layer of vesiculose cells 2-3 deep and
not distinctively colored in KOH. Clamps present.
Type locality. Mazama Ridge, Mt. Rainier National Park, Washington.
Habit and habitat. Solitary on soil on exposed bank of a trail, 5200 ft. elev.
Distribution. Washington.
Observations. This is one of the inconspicuous subalpine species easily overlooked. It is very "ordinary" in most of its features.
378. Psathyrella psilocyboides A. H. Smith, sp. nov.
Pileus 8-12 mm latus, convexus, ad marginem rimosus, glaber, castaneus;
contextu castaneus; lamellae latae, distantes vel subdistantes, fusco-brunneae;
stipes 1-1.5 cm longus, 1 mm crassus, subcastaneus, sparse fibrillosus; sporae
8-10 x 5-6.5 /; pleurocystidia 32-46 x 9-13 /, fusoide ventricosa obtusa vel acuta;
fibulae adsunt. Typus. Smith 65135 (MICH); legit prope Goose Lake, New
Meadows, Idaho.
Pileus 8-12 mm broad, convex, expanding to nearly plane and splitting along
the margin, glabrous, dark chestnut-brown (like a Deconica), fading to dull
cinnamon. Context thin and fragile, colored like the surface.