The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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68. Psathyrella castaneicolor Murrill, Mycologia 14: 272. 1922.
Illust. Text Figs. 175-177.
Pileus 3 cm broad, hemispheric to convex, surface hygrophanous, glabrous or
sometimes having fragments of the white veil when very young, chestnut to tan,
margin even, splitting. Context thin, brownish, with mild but mawkish taste.
Lamellae sinuate adnate, subcrowded, broad, plane, white to purplish then
black.
Stipe 4 cm long, 3-4 mm thick, subcylindric, subglabrous, floccose above,
hollow, white.
Spores 9-12 x 5.5-6.6 x 6.6-8 /, smooth, apical pore broad and apex truncate
under low-power oil-immersion, shape in face view broadly elliptic, in profile
obscurely bean-shaped, color in KOH very soon dark chocolate-color, in Melzer's
bay-red, wall about 0.4,u thick.
Basidia 20-25 x 8.5-10 u, 4-spored, hyaline in KOH. Basidioles somewhat
enlarged but not sufficiently so to be brachybasidioles. Pleurocystidia 38-54x
10-20 u, with a well developed narrow (3-5 u) pedicel, greatly inflated above
this to almost balloon-like varying to utriform, wall thin, hyaline, smooth, the
cell readily collapsing, content not distinctive. Cheilocystidia similar to the
pleurocystidia. Caulocystidia more or less similar to pleurocystidia and not
abundant.
Pileus with a cuticle of vesiculose cells 2-3 deep, walls pale cinnamon in
KOH, smooth; hyphae of subcutis reddish cinnamon in KOH, hyphae smooth
to slightly uneven (in KOH). Clamp connections present. When mounted in
Melzer's no tissue or cells showing any distinctive reaction.
Type locality. Redding, Connecticut.
Habit and habitat. On a pile of decaying leaves.
Distribution. Connecticut, Florida. Type studied.
Observations. The spores remind one of the P. candolleana group, but the
pleurocystidia are abundant and distinctive.
69. Psathyrella praetenuis A. H. Smith, sp. nov.
Pileus 3-5 cm latus, late umbonatus vel convexus, glaber, mellei-brunneus;
lamellae dilute brunneae, in exsiccatis subatratae, confertae, adnatae; stipes
6-12 cm longus, 3-6 mm crassus albidus glaber; sporae 8-11 (-12) x 5-6 t; pleurocystidia 38-47 (-52) x 10-17; cheilocystidia saccata vel vesiculosa, luteotunicata;
fibulae adsunt. Typus. Smith 76781 (MICH); legit prope Priest Lake, Idaho.
Illust. Text Figs. 178-180.
Pileus 3-5 cm broad, obtuse, expanding to plane with the margin spreading
and the disc with a low umbo in age, surface glabrous, moist, hygrophanous,
when young dark honey brown ("buckthorn brown" or darker), fading to
cinnamon-buff but slightly redder over the disc, fading first on disc, in age and
when faded pale date brown. Context very thin and fragile, odor not distinctive,
taste fungoid, with FeSO, no color change.
Lamellae pallid brownish young, dark chocolate-color when mature and
blackish as dried, adnate, close, only moderately broad, very thin, edges even.
Stipe 6-12 cm long, 3-6 mm thick above, evenly and only slightly enlarged
downward, hollow, very fragile, white and unchanging (merely sordid variously
in age), surface naked, veil if present rudimentary (no buttons seen).
Spore deposit dark chocolate-color. Spores 8-11 (-12) x 5-6,u, smooth, hyaline