The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

Pileus cuticle a cellular layer 1-2 cells deep, cells both vesiculose and pedicellate; wall hyaline to weakly cinnamon in KOH, thin and smooth; cell content
not distinctive in KOH or Melzer's. Hyphae of trama with pale cinnamon smooth
walls as revived in KOH. No distinctive reaction on any tissue as revived in
Melzer's. Stipe cortex in KOH containing intercellular small crystals and debris
in distinctive amounts. Clamps present.
Type locality. Pinckney, Michigan.
Habit and habitat. Scattered on sandy soil.
Distribution. Michigan.
Observations. This species has the aspect of P. obtusata but grows on sandy
soil and has a paler pileus.
331. Psathyrella ephemera A. H. Smith, sp. nov.
Pileus 0.5-20 mm latus, late convexus, glaber, pallide cinnamomeus, demum
fusco-cinereus; lamellae latae, subdistantes, brunneolae demum cacaocolor dein
fumoso-brunneae; stipes 1-2 cm longus, 1.5-3 mm crassus, pallidus, fragilissimus;
velum sparsissimum; sporae 8-10x 5-6 /A; pleurocystidia 36-48 x 10-15 /, utriformia; fibulae adsunt. Typus. Hoseney 1401 (MICH); legit prope Chelsea,
Michigan.
Illust. Text Figs. 719-721.
Pileus 0.5-20 mm broad, broadly convex with a decurved margin, expanding
to plane or slightly depressed over the disc, glabrous, even, moist and hygrophanous, pale cinnamon when young becoming avellaneous to dingy cinereous as
spores mature, near vinaceous-drab as dried. Context almost paper-thin and
exceedingly fragile, odor not distinctive.
Lamellae broad, adnate, subdistant, brownish when young but soon cocoacolor and when dried near cinnamon-drab, edges white, fimbriate at first, not
undergoing autodigestion.
Stipe 1-2 cm long, 1.5-3 mm thick, equal, hollow, very delicate, pallid and
not discoloring appreciably over the lower part, thinly fibrillose from remains of
a rudimentary veil.
Spores 8-10x5-6,/, smooth, apical pore distinct and apex with a narrow
truncation, on a few the apical pore terminating a snout-like prolongation, shape
in face view ovate to elliptic, in profile obscurely bean-shaped to obscurely
inequilateral, color in KOH dull cocoa-brown but soon becoming dark chocolatecolor, most containing a medium-sized globule (oil?), in Melzer's tawny or
slightly redder, wall 0.3 /u thick.
Basidia 4-spored, short-clavate, 17-24x8-10 pt, hyaline in KOH. Brachybasidioles present. Pleurocystidia 36-48x10-15 pa, utriform, wall thin, smooth
and hyaline, cell content not distinctive. Cheilocystidia 28-36 x 9-15,x, clavate,
fusoid-ventricose and with obtuse apex, or utriform, hyaline, smooth, thin-walled,
content not distinctive.
Pileus cuticle a layer of cells 1-3 thick, some cells up to 60 pA wide, wall thin,
smooth and hyaline, content not distinctive. Hyphae of the trama pale brownish
vinaceous in KOH, the walls thin but some pigment thickenings occur near the
septa. Clamps present.
Type locality. Chelsea, Michigan.
Habit and habitat. Scattered on black muck in a swamp.
Distribution. Michigan.