The North American species of Psathyrella.

1972]

PSATHYRELLA

349

Lamellae narrow, only moderately close, ascending-adnate, seceding, dingy
cocoa-brown becoming darker, blackish as dried, edges even.
Stipe 3-5 cm long, 1-2 mm thick, equal, slender, weak and fragile, white and
remaining so, naked to unpolished.
Spores 7-9.5 x 4.5-5.5 x 5.5-7 g/, smooth, apical pore distinct and apex truncate
typically, shape in face view broadly ovate to angular-ovate rarely subcircular,
in profile subelliptic to obscurely inequilateral, color in KOH dark cocoa-brown
slowly changing to dark chocolate, in Melzer's dark reddish tawny, wall about
0.3 M/ thick.
Basidia 4-spored, 9-11 K broad, 17-24 p long in old pilei, hyaline. Brachybasidioles present. Pleurocystidia 42-58x 10-17 g, utriform to fusoid-ventricose
with broadly rounded apex, the latter with a coating of granular material over
some small areas of some cystidia, wall hyaline and thin, cell content not distinctive. Cheilocystidia scattered to rare, ~ similar to pleurocystidia.
Hyphae of the pileus context rusty cinnamon in KOH, with incrustations on
the wall and wall thickenings present near the septa. Pileus cuticle of greatly
enlarged cells 1-2 deep, the walls thin, pale dingy ochraceous, and the cell content
not distinctive. Clamp connections present.
Type locality. Near McCall, Idaho.
Habit and habitat. Gregarious under spruce and fir, July.
Distribution. Idaho, Washington.
Observations. The broad often angular spores as seen in face view, are distinctive for a species in this group. The stature when fresh reminded me of
P. candolleana, but the pleurocystidia are abundant and characteristic and the
spores are also different.
Material examined. Idaho: Smith 58673 (Type). Washington: Smith 48078.
321. Psathyrella vesiculocystis A. H. Smith, sp. nov.
Pileus 1.5-4 cm latus, late convexus, cinnamomeo-brunneus; contextu concolor; lamellae confertae, angustae, fuscae, in exsiccatis vinaceo-brunneae; stipes
7-11 cm longus, 3-6 mm crassus, sursum pruinosus, pallidus, deorsum glaber;
sporae 8-9.5 x 4-5 x 5-6.5 g; pleurocystidia 38-65 x 10-18 u, pedicellato-ellipsoidea
vel cylindrica, ad apicerum subverrucosa (processi sparsa vel rara); fibulae
adsunt. Typus. Smith 70089 (MICH); legit prope Burgdorf, Idaho.
Illust. Text figs. 690-694.
Pileus 1.5-4 cm broad, convex, expanding to broadly convex, glabrous, moist,
hygrophanous, more or less cinnamon-brown when moist, fading to dingy tan but
when dried dark vinaceous-brown. Context thin, colored like the surface, fragile,
odor not distinctive.
Lamellae crowded, narrow, adnate at first, fuscous at maturity and when dried
very dark vinaceous-brown (near "bone brown").
Stipe 7-11 cm long, 3-6 mm at apex, equal or nearly so, very fragile, pruinose
above, naked below, watery white to pallid and not discoloring; veil absent.
Spores 8-9.5 x 4-5 x 5-6.5 g, smooth, truncate from a broad apical pore, shape
in face view broadly ovate to obscurely angular-ovate, rarely broadly elliptic, in
profile narrowly somewhat- to obscurely-inequilateral varying to ovate, color in
KOH very dark brown and quickly becoming chocolate-black, in Melzer's dark
rusty brown, wall about 0.3 ug thick.
Basidia 4-spored, 18-23 x8-9.5 /, clavate, hyaline. Pleurocystidia 38-65 x
10-18 /, pedicellate-cylindric, pedicellate-elliptic, or utriform, wall smooth except