The North American species of Psathyrella.

268

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

Spores 13-15 x 7-8.5 gu, smooth, apical pore distinct and apex obscurely truncate, shape in face view elliptic to slightly ovate, in profile obscurely inequilateral
to subelliptic, color in KOH soon dark chocolate-color, in Melzer's rather dark
reddish tawny, wall about 1 / thick.
Basidia 4-spored, 18-24x 10-14,u, hyaline in KOH, clavate above a narrow
pedicel. Brachybasidioles present at late maturity. Pleurocystidia rare and similar to cheilocystidia. Cheilocystidia abundant, 38-56x 10-16 u fusoid-ventricose;
apex acute to subacute; wall thin, smooth and hyaline; cell content at times pink
from soluble material. Caulocystidia ventricose-rostrate; apex acute, smooth as
revived in KOH, thin-walled and hyaline, 28-43 x 9-14 f.
Gill trama regular, the hyphae of enlarged cells, pale to dull rusty brown in
KOH. Pileus having a cuticle of inflated or pear-shaped cells 1-2 deep which are
hyaline over the enlarged portion but may have pale tawny-brown walls at the
base or in the pedicel (as revived in KOH), the cells not arranged in a true
palisade. Context hyphae dark rusty brown in KOH, the walls uneven from
pigment thickenings or minute incrustations. Clamps present. No distinctive
reaction on any tissue when mounted in Melzer's.
Type locality. Europe.
Habit and habitat. Scattered on soil and straw in barnyards and on fertilized
soil.
Distribution. Washington, Wyoming.
Observations. This species is distinguished by its thin veil, non-darkening
stipe, obscurely truncate spores and tendency toward pink tints in age.
Material examined. Washington: W. B. Cooke 19881, 19882; Flett 4-8-41;
Smith 13859, 14080, 14193, 14782. Wyoming: Smith 35271.
228. Psathyrella argentata A. H. Smith, sp. nov.
Pileus 1-2(-3) cm latus, conicus demum plano-umbonatus, glaber, violaceobrunneus, demum atomatissimus; lamellae distantes, latae, pallidae demum
brunneo-griseae; stipes 4-6 cm longus, 1-2.5 mm crassus, pallidus demum argentatus; velum sparsissimum; sporae 14-18 x6.5-8 g; pleurocystidia rarissima,
37-46 x 8-15 f, ventricoso-rostrata; fibulae adsunt. Typus. Smith 53629 (MICH);
legit prope Priest Lake, Idaho.
Illust. Text Figs. 523-525.
Pileus 1-2 (-3) cm broad, obtuse expanding to obtusely conic or planoumbonate (in one), glabrous, moist, hygrophanous, violaceous-brown ("benzo
brown") moist, fading to vinaceous-gray except for the cinnamon-buff disc,
decidely atomate when faded. Context thin, fragile, pallid, odor and taste not
distinctive.
Lamellae distant, broad, adnate, pallid when young, hair brown (dark brownish gray) when mature, edges even and whitish.
Stipe 4-6 cm long, 1-2.5 mm at apex, equal, whitish, silvery in age and base
not darkening, veil rudimentary (a trace found in one button).
Spores blackish in deposit, 14-18 x 6.5-8,/, smooth, apical pore distinct, shape
in face view elongate-elliptic, in profile obscurely bean-shaped to subelliptic, color
in KOH blackish, in Melzer's bay-red, wall about 0.7,L thick.
Basidia 4-spored, 24-35x 10-15 I, hyaline or base of pedicel brownish as
revived in KOH. Pleurocystidia rare to absent, 37-46 x8-15 A, ventricoserostrate (like a basidium with an apical finger-like projection); wall thin, smooth
and hyaline. Cheilocystidia 24-35 x 8-15,u, clavate to broadly fusoid-ventricose