The North American species of Psathyrella.

1972]

PSATHYRELLA

51

Illust. Text Figs. 36-38.
Pileus (1-)3-6(-8) cm broad, obtuse to convex when young, surface covered
by innate "snuff brown" to "bister" (dingy yellow-brown) appressed-fibrillose
scales over the disc and merely with appressed fibrils toward the margin, in age
the margin lacerated somewhat, grayish brown in areas between the dark brown
fibrils, the edge appendiculate at first from submembranous patches of a buff to
dull tawny veil, when dried the entire cap dull dingy cinnamon. Context watery
brownish fading to pallid, odor and taste none, FeSO4 no reaction; KOH on veil
remnants dingy tawny.
Lamellae pallid brownish becoming wood brown and near "Natal brown" (dark
vinaceous-brown) in age, near dull "Mars brown" (rusty cinnamon) as dried,
close, adnate, moderately broad, edges even.
Stipe 3-6 cm long, 3-6 mm thick, equal, fibrous, stuffed, pallid within, surface
whitish overlaid by fine fibrils concolorous with those of the pileus (these are
prominent in some basidiocarps and inconspicuous in others but have always been
found), apex whitish and silky-punctate, base with whitish mycelium.
Spores 6.5-7.5 x 4-4.5 x 4.5-5 g, some slightly compressed, smooth, apical pore
distinct, shape in face view corn-kernel-shaped (wedge-shaped) to ovate (the
angles are then less pronounced), in profile broadly bean-shaped, or in optical
section the ventral line straight, color in KOH fuscous with a weak ochraceous
tint, in Melzer's reddish tawny, wall about 0.2 u thick.
Basidia 4-spored, 25-30x7-8 u, hyaline in KOH. Pleurocystidia abundant,
38-52 x 10-14 x 8-11 u, utriform, apex often subcapitate; wall thin, smooth and
hyaline, content of cells not distinctive in either KOH or Melzer's. Cheilocystidia
mostly clavate-pedicellate to vesiculose-pedicellate, 10-16 g, wide, hyaline, thinwalled; some fusoid-ventricose cells also present and apex acute to rounded,
smaller ventricose cells also present and apex acute to rounded. Caulocystidia
mostly clavate and up to 18 g wide, wall thin and hyaline in KOH, cell content
"empty," length of cells quite variable.
Pileus cuticle a thick layer of inflated cells 4-7 deep, their walls hyaline, the
cell content "empty"; hyphae of the subcutis and trama yellow to hyaline in KOH,
smooth. Hyphae of the veil with ochraceous to ochraceous-brown dissolved pigment, walls smooth and hyaline. Clamp connections present. No distinctive
reaction on any tissue seen in mounts revived in Melzer's.
Type locality. Michigan.
Habit and habitat. Scattered on hardwood logs, August.
Distribution. Michigan.
Observations. This species is close to P. lepidotoides but has distinctly smaller
spores differently colored in KOH. Drosophila sylvestris sensu Kiihner and
Romagnesi (1953) has spores 7-11 (-12) x 4.5-5.7 g, again too large. For comments on Gillet's concept of his own species see P. lepidotoides.
Material examined. Michigan: Kauffman 9-7-07 (paratype for Hypholoma
irregulare); Smith 7135, 7666, 15560, 42212, 49930, 51271, 78076 (Type). New
York: Peck 6-1-11.
18. Psathyrella weberi (Murrill) Singer, Agar. Modern Taxon. 507. 1963.
Atylospora weberi Murrill, Lloydia 5: 153. 1942.
Illust. P1. 9, Fig. c; Text Figs. 41-45.
Pileus 2-4 cm broad, obtusely conic becoming plane or retaining only a slight
umbo, surface dry and covered by appressed to slightly recurved fibrillose scales