The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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to elongated and the apex broadly rounded to obtuse, smooth, hyaline, thinwalled and readily collapsing, content not distinctive in either KOH or in Melzer's.
Cheilocystidia similar to pleurocystidia. Caulocystidia versiform but mostly saccate, clavate or vesiculose, more rarely obtusely fusoid-ventricose, the content
of some with refractive particles (in KOH), some with slightly thickened (0.5,)
wall over apex or upper region generally.
Gill trama with greatly enlarged hyphal cells with pale cinnamon cell sap
when fresh, hyaline revived in KOH or the wall weakly ochraceous and very
weakly encrusted at times; subhymenium cellular with darker content than the
cells of the gill trama when fresh. Pileus with a cuticle of hyaline to yellowish
vesiculose cells about 3 deep, the walls thin and smooth, the cell content not
distinctive as revived in KOH or Melzer's. Hyphae of the context with pale cinnamon colored cell sap when fresh, as revived in KOH the walls weakly ochraceous
and minutely roughened. Clamp connections present. No distinctive reactions
observed on mounts of any tissue in Melzer's.
Type locality. Sol Duc Hot Springs, Olympic National Park, Washington.
Habit and habitat. Densely cespitose in large masses on alder logs and debris.
Distribution. Washington.
Observations. The distinguishing features of the species are the rusty brown
coloration, medium-large spores, very large pleurocystidia, pale cinnamon color
of the cell sap in fresh material of the hyphae of the gill trama, and habit of
growing in large clusters. It appears to be related to P. frustulenta.
Material examined. Washington: Smith 14610 (Type), 16279, 30405.
66. Psathyrella neotropica A. H. Smith, nom. nov.
Drosophila pallidispora Murrill, Mycologia 10: 64. 1918 (not Psathyrella pallidispora
Dennis, 1970).
Illust. Text Fig. 170.
Pileus 3 cm broad, irregular, campanulate, at length spreading at the margin,
surface hygrophanous, silky, very faintly striate, veil forming deciduous flecks on
the young pileus, at first chestnut, fading to pale tan, pallid when dry. Context
thin, with mild but slightly mawkish (subnauseous) taste.
Lamellae adnexed, broad, crowded, pale argillaceous, at length brown.
Stipe 5-6 cm long, 3-5 mm thick, slightly tapered upward, fibrillose, white,
hollow, veil scarcely appendiculate.
Spores 9-12 (-13) x 5-6.5 I, smooth but under a 1.4 NA oil immersion objective
appearing to have discontinuities in the wall as seen in optical section, apical
pore usually distinct because of a bubble of protoplasm which shows in KOH
mounts, shape in face view broadly elliptic to ovate, in profile obscurely inequilateral to faintly bean-shaped, color in KOH ochraceous-hyaline but slowly
developing a gray tone, in Melzer's nearly hyaline to ochraceous; wall thin.
Basidia 4-spored, 10-12 gt broad, hyaline. Brachybasidioles present, 10-13 /u
wide. Pleurocystidia 28-37x 10-14g, utriform to fusoid-ventricose with short
necks and broadly rounded apex, thin-walled, readily collapsing, content not
distinctive. Cheilocystidia similar to pleurocystidia or merely vesiculose, 25-30
x 10-15,, thin-walled, smooth, content not distinctive, readily collapsing. Caulocystidia similar to cheilocystidia.
Pileus with a cuticle of inflated cells one to two cells deep, reviving poorly but
apparently with thin, hyaline, smooth walls and lacking any distinctive content.
Hyphae of trama weakly incrusted and pale tan in KOH. Clamp connections
present. No distinctive color reactions noted in mounts made in Melzer's.