The North American species of Psathyrella.

1972]

PSATHYRELLA

301

typically not as elongated in age. Caulocystidia rare, merely clavate hyphal end
cells. Hyphae of stipe cortex with numerous small to large highly refractive
crystals present in and around them.
Gill trama with a central strand of greatly enlarged hyphal cells (50-90x
15-30 t), hyaline or nearly so in KOH, the walls smooth and thin. Pileus with
a cuticle of vesiculose cells 1-2 deep, the cells 15-30 u or more wide, not arranged
in a palisade but a few with pedicels. Hyphae of the context as revived in KOH
hyaline or nearly so and the walls smooth and thin. Clamps present.
Type locality. Claxton School, Anderson County, Tennessee.
Habit and habitat. Gregarious on chips of pine.
Distribution. Known only from type locality.
Observations. The absence of a veil, gray lamellae, whitish stipe, mostly
utriform pleurocystidia, and hyaline hyphae of the context as revived in KOH
appear distinctive.
269. Psathyrella parvivelosa A. H. Smith, sp. nov.
Pileus 1.5-3 cm latus, conicus vel plano-umbonatus, sparse fibrillosus glabrescens, pallide spadiceus demum fusco-griseus; lamellae pallidae vel brunneolae
demum cinnamomeo-griseae; latae, confertae; stipes 3-5 cm longus, 2-4 mm
crassus, candidus, adpresse fibrillosus, deorsum intus griseus, sporae 9-11 5-6,u;
pleurocystidia 50-70 x 12-20 /u, late ventricosa ad apicerum obtuse vel rotundata;
fibulae adsunt. Typus. Smith 34861 (MICH); legit prope Libbey Creek,
Centennial, Wyoming.
Illust. P1. 78, fig. d; Text Figs. 571-574.
Pileus 1.5-3 cm broad, obtusely conic when young, expanding to broadly conic
or nearly plano-umbonate, surface at first thinly covered with white veil remnants
which disappear without forming squamules, margin fringed at first, color when
young "buckthorn brown" (honey brown) to pale Verona brown (dull cinnamon),
becoming wood brown (grayish brown) to dark grayish brown ("hair brown"),
fading to grayish. Context pallid, fragile, thin, odor and taste not distinctive.
Lamellae pallid to brownish and finally near cinnamon-drab, close, ascendingadnate to nearly horizontally-adnate in age, moderately broad, readily seceding
edges whitish.
Stipe 3-5 cm long, 2-4 mm thick, slightly enlarged downward, shining white
from a thin fibrillose coating which does not completely disappear, watery gray
at the base within, no distinctive color changes observed on bruising.
Spores 9-11 x 5-6 u, smooth, apical pore small and apex not truncate, shape
in face view ovate to elliptic, in profile mostly somewhat inequilateral, in KOH
dull cocoa-color but darkening slowly to a medium chocolate-brown, in Melzer's
dark tawny to amber brown, wall about 0.4,u thick.
Basidia 4-spored, 20-25 x 8-9,u, hyaline in KOH, clavate. Pleurocystidia
abundant, 50-70 x 12-20 1, broadly ventricose and evenly narrowed to an obtuse
or broadly rounded apex, or fusoid-ventricose with obtuse apex, wall thin, smooth
and hyaline, content somewhat colloidal in KOH, not distinctive in Melzer's.
Cheilocystidia similar to pleurocystidia or more of them fusoid-ventricose with
apex subacute to subcapitate. Caulocystidia subcylindric to broadly clavate or
some with a lateral protuberance or branch, wall thin, smooth and hyaline, cell
content not distinctive.
Pileus having a cuticle of a layer of vesiculose cells several deep, their walls
smooth, thin and hyaline, their content not distinctive in KOH or Melzer's.