The North American species of Psathyrella.

1972]

PSATHYRELLA

417

brown, moist, fading to reddish tawny over the disc and duller over the margin,
atomate when faded. Context exceedingly thin and fragile, odor and taste not
distinctive, with FeSO4 no color change.
Lamellae broad, close to subdistant, adnate, pallid, brownish becoming "benzo
brown" (violaceous fuscous), edges even.
Stipe 4-6 cm long, 2-3.5 mm thick, equal, fragile, pallid and dull but brownish
only at the base, naked to only faintly pruinose at apex, veil none.
Spores 8-10 x 4-5,u, smooth, apical pore distinct and spore apex often truncate,
shape in face view elliptic to ovate, in profile obscurely bean-shaped to obscurely
inequilateral, color in KOH dark chocolate-color immediately upon being mounted,
in Melzer's bay-brown (very dark reddish brown), wall about 0.3 ju thick.
Basidia 4-spored, 15-20x6-8 Iu; short-clavate. Brachybasidioles up to 12 ju
wide present at maturity. Pleurocystidia 36-47(-55) x8-12(-14),/, narrowly
subfusoid to fusoid-ventricose, apex obtuse to subacute, wall thin, smooth and
hyaline, content not distinctive in KOH or Melzer's. Cheilocystidia 32-44x
9-12 u, similar to pleurocystidia but shorter and hence appearing more broadly
fusoid-ventricose. Caulocystidia mostly as terminal cells of a chain of inflated
cells, the latter being 10-18, wide, end cells vesiculose, clavate to fusoidventricose, hyaline smooth, thin-walled, content not distinctive.
Pileus cuticle a layer of inflated cells 1-2 deep, the walls hyaline to pale
ochraceous-cinnamon as revived in KOH, content of cell not distinctive, walls
thin and smooth. Context (including subcuticular region) of hyphae vinaceouscinnamon in KOH and typically with roughened walls. No distinctive reaction
on any tissue as revived in Melzer's. Clamps present.
Type locality. Warren, Idaho.
Habit and habitat. Gregarious on grassy soil.
Distribution. Idaho.
Observations. This is a very commonplace terrestrial species in which by
maturity the basidioles inflate considerably. The pleurocystidia are characteristically narrow, and the rich chestnut color of the moist pileus is reflected in the
pigmentation of the pilear trama as revived in KOH. The caulocystidia are its
most unusual feature-as cells terminating a chain of inflated cells.
394. Psathyrella griseopallida Thiers & A. H. Smith, sp. nov.
Pileus 1-3 cm latus, late convexus, argillaceus demum triste griseus dein
pallidus; lamellae latae, pallidae demum fuscae, confertae; stipes 2-3 cm longus,
2-4 mm crassus, albus, pruinosus; velum nullum; sporae 8-10x4-5 t; pleurocystidia 42-56 x 10-17 a, obtuse vel subacute fusoideo-ventricosa; fibulae adsunt.
Typus. Thiers 25079 (MICH); legit prope Lake Henshaw, San Diego County,
California.
Pileus 1-3 cm broad, convex becoming broadly convex, glabrous moist and
hygrophanous, clay color before becoming drab-gray from maturing spores, fading
to pallid, cinereous to darker (or if young pallid) on drying, becoming sulcate
striate, margin entire and naked. Context thin and fragile (1-2 mm in disc), taste
and odor mild.
Lamellae broadly adnate to adnexed, close to subdistant, narrow to moderately
broad, pallid becoming pale fuscous, drying a fuscous-gray, edges even.
Stipe 2-3 cm long, 2-4 mm thick, equal, white, unchanging, fragile, dry, naked,
pruinose above at first; no veil evident.