The North American species of Psathyrella.

1972]

PSATHYRELLA

121

drab"), close, narrow or finally moderately broad, adnate, soon seceding, edges
whitish.
Stipe 3-6 cm long, 3-7 mm thick, hollow, rigid but fragile, pallid within, at
first snow white and fibrillose but soon dingy brownish below, fibrillose to a baggy
submembranous veil (reminding one of Suillus subluteus) when breaking sometimes adhering as an annulus but usually adhering as fragments on the margin of
the pileus.
Spores 6-7 x 3-3.5,u, smooth, apical pore present but very inconspicuous (under
oil immersion), shape in face view narrowly elliptic or more rarely ovate, in
profile subelliptic to obscurely elongate-inequilateral, color in KOH dull cocoacolor darkening to dark chocolate-color, in Melzer's reddish tawny, wall about
0.2 i thick.
Basidia 4-spored, 13-20 x 6-7,u, clavate, hyaline in KOH. Pleurocystidia
42-60 x (9-)10-17 1A, fusoid-ventricose with apex acute and long retaining hyaline
incrusting granules as viewed in KOH, walls thin and hyaline, content not distinctly differentiated in KOH or Melzer's. Cheilocystidia similar to pleurocystidia
only shorter. Caulocystidia versiform and variable as to size.
Pileus cuticle a layer of inflated cells 3-5 deep, the walls thin, smooth and
usually ochraceous to hyaline in KOH, content of cell not distinctive. Hyphae
of subcutis vinaceous-cinnamon in KOH but fading, walls smooth, cell content not
distinctive. No distinctive reaction present in any tissue when revived in Melzer's.
Clamps present.
Type locality. Stutsmanville, Emmet County, Michigan.
Habit and habitat. Gregarious on a birch log, June.
Distribution. Known only from type locality.
Observations. The diagnostic features of this variety are the denticulate veil
remnants usually present on the pileus margin for a short time after the veil
breaks, the large pleurocystidia with granules tending to adhere to the apex and
the apex reviving more slowly than the rest of the cell, the pale cinnamon-brown
pileus and the stipe brunnescent below.
77. Psathyrella subfilipes A. H. Smith, sp. nov.
Pileus 5-15 mm latus, obtuse conicus demum late conicus vel subplanus, albofibrillosus, cinnamomeo-brunneus; lamellae adnatae, confertae, latae, sordide fulvae; stipes 8-17 mm longus, circa 1 mm crassus, albo-fibrillosus intus sordide
brunneus; sporae 4.5-5.5 x 2.8-3.2,u; pleurocystidia 30-46 x 7-14 p,, acuta; fibulae
adsunt. Typus. Smith 42710 (MICH); legit prope Mackinaw City, Michigan.
Pileus 5-15 mm broad, obtusely conic expanding to broadly conic, convex or
nearly plane, surface at first covered by copious white fibrillose remains of an
outer veil, cinnamon-brown beneath the veil remnants when moist and fading to
a dull tan, glabrescent in age. Context thin and fragile, dark brown when moist.
Lamellae adnate, close, moderately broad, becoming ventricose on expanded
pilei, dull russet before becoming clouded by the spores, fuscous-brown as dried,
edges pallid.
Stipe 8-17 mm long, about 1 mm thick, equal, fragile, dull brown beneath the
pallid fibrillose remains of the veil.
Spore deposit purple-brown. Spores 4.5-5.5 x 2.8-3.2 /, smooth apical pore not
evident, shape in face view wedge-shaped to ovate, varying to elliptic, in profile
subelliptic to obscurely inequilateral, color in KOH a dingy chocolate-brown, in
Melzer's pale tawny wall 0.2 tu or less thick.