The North American species of Psathyrella.

1972]

PSATHYRELLA

357

Spores 7-9 x 4.2-5 p, smooth, apical pore distinct but apex not truly truncate,
shape in face view oblong to subelliptic, in profile obscurely bean-shaped, color
in KOH cocoa-color slowly going to medium chocolate, dull reddish tawny in
Melzer's, wall about 0.2, thick.
Basidia 4-spored, short-clavate, 16-20x6-8 a, hyaline. Pleurocystidia 38 -50 x 12-16 x 8-11 a, utriform to broadly fusoid-ventricose with rounded apex, wall
thin, smooth and hyaline, content not distinctive. Cheilocystidia mostly clavate
and up to 18 jL wide but some narrowly fusoid-ventricose cells 30-42 x 7-10 E/ also
present, their necks 3-4 I wide, both types hyaline in KOH.
Pileus cuticle a layer of vesiculose cells 12-30 u wide, some pedicellate, walls
thin and hyaline, content not distinctive. Hyphae of subcuticular zone rusty
brown in KOH, hyphal walls mostly smooth. Clamps present.
Type locality. Near Otsego, Allegan County, Michigan.
Habit and habitat. Scattered to gregarious in open pastures (with Phleum
pratense and Dactylis glomerata).
Distribution. Known only from the type locality.
Observations. This species is close to P. spadiceogrisea but the spores are too
narrow and the habitat is also atypical, in fact the different ecological aspects of
both are quite marked. In addition the veil appears to be even more poorly
developed than in P. spadiceogrisea.
330. Psathyrella psammophila A. H. Smith, sp. nov.
Pileus 8-20 mm latus, late conicus, glaber melleus vel melleibrunneus; contextu
cum "FeSO," olivaceo-griseus; stipes 1-2.5 cm longus, 1-2.5 mm crassus, pallidus,
deorsum sparse fibrillosus glabrescens; velum sparsum; sporae 7-8x4.5-5 /;
pleurocystidia 46-62x9-15 a, utriformia vel obtuse fusoide ventricosa; fibulae
adsunt. Typus. Smith 67836 (MICH); legit prope Pinckney, Michigan.
Illust. P1. 88, fig. c; Text Figs. 715-718.
Pileus 8-20 mm broad, obtusely conic expanding to broadly conic, the margin
straight, veil rudimentary and not leaving significant traces on the pileus, surface
glabrous, moist and hygrophanous, pale honey brown fading to pale buff or
whitish, older pilei striate before fading, atomate after fading. Context very thin
and fragile, odor and taste not distinctive, FeSO4 causing a color change to pale
olive-buff.
Lamellae broad, close, adnate then seceding, pallid brown, becoming wood
brown (dark brownish gray) at maturity, edges whitish.
Stipe 1-2.5 cm long; 1-2.5 mm thick, equal or nearly so, very fragile, pruinose
above, thinly fibrillose lower down, base hardly darkening (merely dingy
ochraceous in age); veil rudimentary.
Spores 7-8x4.5-5 I, smooth, apical pore present but apex rounded, in face
view broadly elliptic to ovate, in profile more or less obscurely bean-shaped, color
in KOH cocoa-color, slowly darkening to chocolate-brown (smoky cocoa-color),
reddish tawny in Melzer's, wall about 0.2 [u thick.
Basidia 4-spored, 9-12 j wide at apex, clavate, hyaline. Pleurocystidia
46-62x 9-15 A, utriform to obtusely fusoid-ventricose, smooth or rarely with a
slight mucilaginous coating over or near the apex, hyaline, thin-walled, content
not distinctive in KOH or in Melzer's. Cheilocystidia clavate to obtusely fusoid
or fusoid-ventricose, smooth, thin-walled, hyaline in KOH. Caulocystidia mostly
clavate, thin-walled, hyaline, of various sizes, some "mitten-shaped" in optical
section.