The North American species of Psathyrella.

1972]

PSATHYRELLA

209

to narrowly fusoid-ventricose, apex obtuse to subacute, wall thin, smooth and
hyaline, cell content not distinctive in KOH or Melzer's. Caulocystidia in
clusters, 38-64 x 7-12 /, flexuous-clavate or branched 1-2 times at apex or merely
with rudimentary protuberances, hyaline, thin-walled.
Gill trama regular, the hyphae 8-15 / wide and subparallel, pale cocoa-color
fading to sordid cinnamon-brown to hyaline when revived in KOH. Pileus having
a cuticle of hyaline or very pale brown vesiculose cells 15-30 / wide, the layer
1-2 cells deep, walls smooth and thin and cell content not distinctive. Hyphae
of the subcuticular region with smooth pale cinnamon walls (the layer cocoa-color
when first revived in KOH). Clamp connections present. No distinctive reactions
on any tissue when mounted in Melzer's.
Type locality. Elwha River Ranger Station, Olympic National Forest,
Washington.
Habit and habitat. Solitary to gregarious on humus under alder and
cottonwood.
Distribution. Idaho, Oregon, Washington.
Observations. In Smith 73932 from Priest Lake, Idaho, the pleurocystidia
have very thin walls at and near the apex, and the apical region is granularroughened as revived in KOH. The side walls are refractive in KOH and about
0.3 / thick. It was found on decaying alder.
Material examined. Idaho: Smith 73932. Oregon: Smith 19339. Washington:
Smith 14024, 14115, 14184 (Type), 14248,14589, 16295.
166. Psathyrella citrinovelata A. H. Smith, sp. nov.
Pileus 1-3 cm latus, convexus, cinnamomeo-brunneus, fibrillosus vel subsquamulosus (velum pallide citrinum), ad marginem sparse appendiculatus vel
fimbriatus; lamellae brunneolae demum violaceo-fuscae; stipes 3-7 cm longus,
2-4 mm crassus, albidus, copiose fibrillosus, glabrescens, sursum fibrillosoannulatus; sporae 7-9 4-4.5 f/; pleurocystidia 38-52 x12-16 /, fusoide ventricosa, ad apicerum late rotundata; fibulae adsunt. Typus. Smith 25392 (MICH);
legit prope Harbor Springs, Michigan.
Illust. Text Figs. 372-374.
Pileus 1-2 cm broad, convex, cinnamon-brown moist, hygrophanous fading to
a grayish cinnamon-buff, surface at first decorated with conspicuous very pale
lemon yellow fascicles of the remains of the fibrillose outer veil, the margin also
slightly appendiculate with yellowish veil remnants. Context thin, fragile, brownish fading to pallid, odor not noticeable, taste not recorded.
Lamellae close, broad, adnate, pallid brownish becoming dark brownish
violaceous ("benzo brown"), edges whitish.
Stipe 3-7 cm long, 2-4 mm thick, equal, white, very densely squamulose with
yellowish veil remnants to the subannular zone left by the broken partial veil,
densely white-squamulose above this zone to near the apex.
Spores 7-9x 4-4.5 p/, smooth, apical pore present but apex rounded, shape in
face view elliptic to slightly ovate, in profile somewhat inequilateral to obscurely
so, color in KOH dull cocoa-color slowly changing to chocolate-brown, in Melzer's
tawny to reddish tawny, wall about 0.3 / thick.
Basidia 4-spored, 15-20 x7-9 /u, clavate, hyaline in KOH. Pleurocystidia
scattered, 38-52x 12-16 /x, fusoid-ventricose with broadly rounded apex, in age
the neck elongated somewhat but apex rounded to obtuse, wall thin, hyaline and
smooth, cell content not distinctive in KOH or in Melzer's. Cheilocystidia 50 -