The North American species of Psathyrella.

1972]

PSATHYRELLA

311

becoming dull dark avellaneous to chocolate-brown, fading to buff ("pinkish
buff") and soon tinged pinkish at least along the margin, conspicuously translucentstriate when fresh, opaque when faded and then usually sulcate along the margin
and somewhat rugulose. Context very thin and fragile, pallid, odor and taste not
distinctive.
Lamellae broad, adnate, subdistant, pallid becoming blackish, edges white at
first but pink in age.
Stipe 3-5 cm long, 1-1.5 mm thick, equal, very delicate and fragile, white and
translucent, finally sordid in age, glabrous, apex faintly pruinose at first.
Spores 10-13 x 5-6.5 /g, smooth, apex truncate from a broad apical pore, shape
in face view oblong to elliptic, in profile obscurely inequilateral, color in KOH
date brown but gradually darkening to blackish brown, in Melzer's tawny or
slightly redder, wall about 1 a thick.
Basidia 4-spored, 9-12 / wide, clavate, hyaline in KOH. Pleurocystidia
36-48 x 10-16 g, fusoid-ventricose with acute apex, hyaline, thin-walled, smooth,
content not distinctive in KOH or in Melzer's. Cheilocystidia either similar to
pleurocystidia or cylindric to clavate or saccate and then 12-20x6-18 g, the
pedicels and the smaller cells usually with yellowish walls as revived in KOH.
Caulocystidia scattered and resembling the cheilocystidia except for being hyaline
in KOH.
Gill trama regular, pale cinnamon-brown to nearly hyaline in KOH (fading
on standing and paler in old basidiocarps). Pileus trama pale cinnamon-brown
to pallid, in the subcuticular region the walls roughened at least on some of the
narrower hyphae. Cuticle of the pileus a layer of vesiculose cells irregularly one
cell deep and not arranged in a distinct palisade. Clamps present. No distinctive
reactions noted for any tissue as revived in Melzer's.
Type locality. France.
Habit and habitat. Scattered to gregarious on wet earth in shady places.
Distribution. Michigan, Tennessee, Washington, Wyoming.
Observations. American material has not been subjected to a detailed comparison with authentic European specimens, but there is nothing in the original
description which would exclude my specimens from being placed in this species.
Romagnesi mentioned 2-spored basidiocarps whereas ours were 4-spored, but this
situation is to be expected in many species in the genus.
Material examined. Michigan: McCrea 7-1-45, 7-10-45; Smith 21236, 21907,
21967, 22317, 26018, 26024, 26173, 26188, 26189. Tennessee: Smith 10773. Washington: Smith 13188, 14682, 31199. Wyoming: Solheim 4194.
281. Psathyrella pseudolongipes A. H. Smith, sp. nov.
Pileus 3-4.5 cm latus, conicus, subspadiceus, glaber; lamellae confertae, angustae, griseo-brunneae demum atro-brunneae; stipes 9-10.5 cm longus, 3-3.5 mm
crassus, fragilissimus, dissiliens, albidus, sursum pruinosus; velum nullum; sporae
10-12.5 x 4.5-6 p.; pleurocystidia 42-68 x 9-18 I, fusoideo-ventricosa obtusa; fibulae adsunt. Typus. Smith 16611 (MICH); legit prope Baker Lake, Mt. Baker,
Washington.
Illust. Text Figs. 599, 600.
Pileus 3-4.5 cm broad, obtusely conic and not expanding, surface glabrous,
hygrophanous, "buckthorn brown" moist, pallid ("tilleul buff") except for the
yellowish disc when faded. Context thin, concolorous with the surface, extremely
fragile, no distinctive odor or taste present.