The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

inequilateral to subelliptic, color in KOH pale cocoa-color slowly changing to
fuscous-gray (pale), reddish tawny in Melzer's, wall about 0.2,u thick.
Basidia 4-spored, short, 12-18x 7-9 1A. Brachybasidioles possibly present in
age. Pleurocystidia none. Cheilocystidia 30-46 x 10-16 /, utriform to subcylindric
clavate, hyaline and thin-walled.
Gill trama of hyaline smooth interwoven inflated hyphae in KOH; subhymenium cellular, the cells up to 15 tu or more in diameter (often twice the
diameter of a basidium). Pileus cuticle a layer 1-3 cells deep of inflated hyaline
thin-walled cells. Subcuticular hyphae hyaline in KOH. Clamps present.
Type locality. Dexter, Michigan.
Habit and habitat. Subcespitose to gregarious near elm stumps, late June.
Distribution. Known only from the type locality.
Observations. This species has extremely small basidia in relation to the size
of the subhymenial cells. In fact it is difficult to identify brachybasidioles because
subglobose hymenial cells were seen to have sterigmata. The spores in face view
are more elliptic than in P. candolleana, the young pileus is olive-tinged, and an
annulus is usually present. Psathyrella leucotephra (Berk. & Br.) Orton may be
close to this species, but the stipe is squamulose below the annulus.
38. Psathyrella tuberculata (Patouillard) A. H. Smith, comb. nov.
Hypholoma tuberculatum Patouillard, Bull. Soc. Mycol. Fr. 15: 196. 1899.
Stropharia tuberculata Morgan, Jour. Mycol. 14: 70. 1908.
Illust. Text Figs. 110, 111.
Pileus 1-4 cm broad, fleshy, at first globose, becoming campanulate and finally
expanded, greenish and covered with squamules in the form of small obtuse
tubercules, becoming glabrous and color changing to purplish or almost black,
smooth or faintly striatulate, the margin entire and straight. Context thin.
Lamellae narrow, reaching the apex of the stipe, white then purplish and finally
a brownish black.
Stipe 5-10 cm long, 3-5 mm thick, white, cylindric, hollow, fragile, rugulose
and lower portion marked with scattered slightly projecting squamules; annulus
spreading, thin, membranous, fringed on the margin, white, persistent, median to
somewhat superior.
Spores 6.2-7.8 x 4-4.6 )L, smooth, pore apical and distinct under oil immersion,
shape in face view elliptic, color as revived in KOH dull cocoa-color becoming
chocolate-gray, in Melzer's tawny reddish.
Basidia 4-spored, 13-15 x 5-6 p, hyaline in KOH. Brachybasidioles possibly
differentiated by maturity (hymenium in old pilei very poorly preserved).
Pleurocystidia none. Cheilocystidia scattered, 16-22 x 9-12 p, clavate to broadly
fusoid-ventricose, apex rounded to obtuse, wall thin, smooth and hyaline, content
not distinctive. Caulocystidia not studied.
Pileus with a cuticle of clavate-pedicellate and vesiculose cells about one cell
deep, their walls smooth, thin and hyaline as revived in KOH. Hyphae of the
subcuticular zone dull tawny brownish as revived in KOH.
Type locality. Guadeloupe.
Habit and habitat. Cespitose on old trunks of Hura crepitatus.
Distribution. Guadeloupe (type studied).
Observations. The greenish color of the pileus is admittedly peculiar for a
Psathyrella, but the material studied clearly indicates this genus.