The North American species of Psathyrella.

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in mature pilei brachybasidioles are present. Also, the young pileus is fibrillose
and the lamellae narrow and crowded.
Material examined. California: McClatchie (Type); Morse 1937, 3-16-38;
Michigan: Smith 36118. Oregon: Smith 19035. Washington: Smith 30430.
53. Psathyrella fragilissima (Kauffman) A. H. Smith, comb. nov.
Psathyra fragilissima Kauffman, Pap. Mich. Acad. Sci. 5: 142. 1926.
Illust. 1. c., pl. 11. Text Figs. 137, 138.
Pileus 2-5 cm broad, 1.5-3 cm high, at first broadly conic and obtuse, coniccampanulate at maturity, hygrophanous, "light cinnamon-drab" and even when
moist and young, later "benzo brown" (dull purplish brown), at first covered
by snow-white evanescent floccose-fibrillose superficial scales, soon glabrous,
fading to "pale pinkish buff" and even when faded, margin at times evanescently
appendiculate. Context thin, very fragile, equal, concolorous with surface, odor
and taste mild or slightly nutty.
Lamellae ascending, adnate-seceding, relatively narrow (3-5 mm), crowded,
soon "hair brown" then "fuscous" (violaceous-black), edge at first minutely
white flocculose.
Stipe 10-15(-18) cm long, 3-5(-6) mm thick, long and slender, extremely
fragile, equal or slightly tapering upward, pure white, glabrous, scurfy and substriate at apex, hollow, even, strict but becoming flexuous, cartilaginous, easily
splitting.
Spores 13-15 x 6-7x 7-8.5 u, smooth, apical pore distinct and apex truncate,
shape in face view broadly elliptic to subovate, in profile subelliptic or the suprahilar area broad and flattened, color in KOH fuscous-brown becoming chocolateblack, in Melzer's very dark reddish brown, wall about 0.5-0.7 pi thick.
Basidia 30-32 x 10-12,, 4-spored, hyaline in KOH. Pleurocystidia none.
Cheilocystidia abundant, 32-45 9-15 E/, broadly fusoid-ventricose to utriform,
wall thin, smooth and hyaline, cell content not distinctive in KOH or Melzer's.
Caulocystidia not found in the material examined (type).
Pileus with a cuticle of vesiculose hyaline cells 3-4 cells deep, their walls
thin, smooth hyaline and not refractive, cell content not distinctive. Hyphae of
the context only slightly brownish as revived in KOH and fading on standing, walls
thin and not refractive.
Type locality. Mt. Hood, Oregon.
Habit and habitat. Gregarious on decayed leaves etc. in mixed forests.
Distribution. Oregon.
Observations. This species is easily mistaken for a Pannucia, no doubt
because that is where its relationships appear to be. Hence it is keyed in both
groups. Psathyra fragilissima Lange (1936); Lange's species is now identified
with Psathyrella marcescibilis (Britz.) Singer.
Material examined. Oregon: Sipe 766; Smith 28414; Kauffman's type from
Mt. Hood.
54. Psathyrella elwhaensis A. H. Smith, sp. nov.
Pileus 2.5-7 cm latus, obtusus demum late conicus vel campanulatus, glaber,
ad marginem appendiculatus, avellaneus vel subavellaneus demum cinnamomeobrunneus; lamellae confertae angustae adnatae, albidae demum fuscae; stipes
9-16 cm longus, 3-6 mm crassus, cavus, fragilis albidus, glaber; sporae 12-15 x
6.5-8 I; cheilocystidia 30-42 x 8-12 (-17) IL; fibulae adsunt. Typus. Smith 3318
(MICH); legit prope Port Angeles, Washington.