The North American species of Psathyrella.

1972]

PSATHYRELLA

229

ing to clavate or subelliptic (in optical section), content not distinctive, wall thin,
smooth and hyaline. Caulocystidia present as scattered clavate hyphal end cells.
Pileus with a cuticle of inflated cells 3-5 deep, those over the surface with
practically hyaline walls, those toward the subcuticular zone pale cinnamon and
smooth or with only scattered pigmented thickenings. Hyphae of the subcuticular
zone pale cinnamon to reddish cinnamon in KOH and with pigmented wall thickenings especially near the cross walls; cell content not distinctive. Clamp connections present. No distinctive reaction on any tissue as mounted in Melzer's.
Type locality. Bear Springs, Mt. Hood National Forest, Oregon.
Habit and habitat. Cespitose-gregarious on wet soil, October.
Distribution. Known only from the type locality.
Observations. Psathyrella subcaespitosa differs from P. frustulenta in the gray
tone of the fresh gills, in the thick partial veil, and clustered habit of growth.
186. Psathyrella umbrinescens A. H. Smith, sp. nov.
Pileus 1-3 cm latus, acute conicus demum campanulatus, interdum convexus,
fibrilloso-squamulosus, glabrescens, cinnamomeo-brunneus, denique violaceoumbrinus; lamellae confertae, angustae demum latae, brunneolae dein atrobrunneae; stipes 3-6 cm longus, 2-3 mm crassus, pallidus fibrillosus, glabrescens;
sporae 7-9x4-5 /A; pleurocystidia 38-52x12-18 u, late fusoidea, subacuta, vel
fusoideo-ventricosa; fibulae adsunt. Typus. Smith 50422 (MICH); legit Tahquamenon Falls State Park, Michigan.
Pileus 1-3 cm broad, sharply to obtusely conic expanding to campanulate or
convex, margin curved in slightly at first and then copiously decorated with veil
remnants, squamules from the pallid veil at first decorating the entire pileus but
these soon vanishing, surface moist and hygrophanous, dull cinnamon-brown
fading to dingy tan and then slowly becoming umber, dark violaceous-umber as
dried. Context very thin and fragile, odor and taste not recorded.
Lamellae crowded, narrow, becoming moderately broad, dull brown when
young, blackish brown as dried, edges even.
Stipe 3-6 cm long, 2-3 mm thick, equal, slender, very fragile, whitish drying
violaceous-cinereous, appressed fibrillose to the veil line at first, glabrescent, apex
slightly pruinose.
Spore deposit chocolate-fuscous; spores 7-9 x 4-5 /, smooth, apical pore distinct and apex truncate, shape in face view elliptic to almost oblong, in profile
obscurely inequilateral to elliptic, color in KOH very dark rich rusty brown slowly
becoming dark chocolate-color, in Melzer's bay-brown, wall about 0.3 It thick.
Basidia 4-spored, 18-24x8-9 u, short-clavate, hyaline. Pleurocystidia scattered, 38-52 x 12-18,u, broadly fusoid to a subacute apex or fusoid-ventricose,
walls thin, smooth and hyaline, cell content not distinctive. Cheilocystidia mostly
fusoid-ventricose, 32-45 x 9-15 /, fusoid-ventricose with subacute to obtuse apex.
Pileus cuticle a layer of vesiculose cells 2-3 deep, the walls more or less ochraceoustan or paler, thin-walled and smooth. Hyphae of the subcuticular area hyaline
to brownish in KOH, the wall smooth. Clamp connections present.
Type locality. Tahquamenon Falls State Park, Luce County, Michigan.
Habit and habitat. Gregarious on mud, Michigan.
Distribution. Known only from the type locality.
Observations. This species is distinguished by the violaceous-umber pileus as
dried, copious outer veil which soon vanishes, very thin delicate stipe, broadly
fusoid pleurocystidia and very dark rusty brown spores as first revived in KOH.