The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Pleurocystidia abundant, 60-90 x 10-16 A, subutriform to fusoid-ventricose with
rounded to obtuse apex, at times subcylindric, the wall thin, smooth and hyaline
(or rarely some debris adhering near the apex), content not distinctive in either
KOH or Melzer's. Cheilocystidia similar in shape to pleurocystidia but usually
smaller. Caulocystidia not located. Cortex of stipe of hyphae with fuscous brown
wall thickenings (or incrustations) near the septa (as revived in KOH).
Pileus with a cuticle of vesiculose cells having thin, smooth, hyaline walls
and lacking a distinctive content in either KOH or Melzer's as revived, some
clavate to pyriform cells intermingled in the layer. Context of hyphae with
grayish brown to fuscous-brown deposits of pigment or wall thickenings particularly near the septa but also incrusting the hyphae as zones or bands, cell content
not distinctive in either KOH or Melzer's as revived. Clamps present.
Type locality. Europe.
Habit and habitat. Gregarious to cespitose on soil and humus.
Distribution. Washington.
Observations. Malenqon and Romagnesi (1953) illustrated the cystidia of
both P. barlae and P. bipellis Quel. Those of the latter species would place it in
a different section in my classification. Since I have found a difference of the
type these authors illustrated, to be, on the whole, a very constant feature in
North American Psathyrellae, I continue to recognize P. barlae as a distinct
species, but now recognize the collections from the Great Lakes region previously
referred to as P. bipellis as forma minor of P. barlae. This species and its variants
are intermediate in veil features and have also been keyed out in subg. Psathyrella
to facilitate identification.
Material examined. Washington: Smith 14247, 14326, 14525, 14811, 14849.
62a. Psathyrella barlae f. minor A. H. Smith, f. nov.
Pileus 1-4 cm latus, stipes 2-3 mm crassus; lamellae rubellae demum fuscobrunneae. Typus. Smith 1389 (MICH); legit prope Ann Arbor, Michigan.
Illust. PI. 75, fig. b.
Pileus 1-4 cm broad, obtusely conic, the margin appressed against the stipe
becoming somewhat expanded, often with an obtuse umbo, at first with scattered
fibrils over the surface and a fibrillose zone near the margin from the broken
veil, glabrous in age, when young and fresh dark purplish-red ("diamine brown")
but sometimes becoming rusty brown ("Mars brown") before fading, hygrophanous, fading to "light grayish vinaceous" before fading (pinkish gray). Context
reddish when moist, very fragile, taste not distinctive, odor faintly fragrant.
Lamellae moderately close to subdistant, broad, adnate or narrowed at the
point of attachment, bright pink (near "Corinthian pink") at first, becoming dark
brown with a persistent reddish tinge, edges minutely white-fimbriate.
Stipe 1-4 cm long, 2-3 mm thick, tubular, very fragile, pallid but with a
vinaceous to pink tinge, at first fibrillose, canescent part way to apex, with
scattered fibrillose points above, nearly glabrous in age.
Spores 12-15 (-16) x 6-7.5 (-8) 1/, smooth, pore apical to oblique, well developed, shape in face view elliptic to suboblong, in profile subelliptic to very
obscurely inequilateral, color in KOH bister becoming dark coffee-brown, in
Melzer's dark bay, wall about 0.4 / thick.
Basidia 4-spored, 20-30 x 10-14 /, many almost globose above a narrowed
pedicel. Pleurocystidia scattered, 50-70 X 10-18 a, more or less fusoid-ventricose,
or the neck constricted only slightly and apex rounded to somewhat capitate,
wall thin, smooth and hyaline, and content not distinctive in KOH or in Melzer's.
Cheilocystidia similar to pleurocystidia but usually smaller. Caulocystidia