The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Lamellae adnate, soon seceding, crowded, 28-36 reach the stipe, moderately
broad (about 4-8 mm), 3 tiers of lamellulae, whitish at first, then pinkish buff
finally becoming dull vinaceous-brown, duller brown as dried, edges even.
Stipe 8-14 cm long, 3-8 mm thick, equal, often curved at base, hollow, fragile,
pure white when young, slightly sordid in age, faintly fibrillose but soon
glabrescent, base white-mycelioid.
Spores 6.5-8(-9) x 4-4.5 x 4.5-5 A, at the most only very slightly flattened,
smooth, apical pore minute and inconspicuous under oil (apex rounded), shape
in face view ovate to elliptic, in profile obscurely bean-shaped to obscurely
inequilateral, color in KOH bister or darker, finally clouded chocolate-gray, in
Melzer's tawny, wall about 0.3 K thick.
Basidia 17-22x7-9 t, short-clavate, hyaline in KOH. Pleurocystidia abundant, 40-70x 8-15 gL, fusoid-ventricose with obtuse to subacute apex, often with
debris adhering near apex (revived in KOH), wall thin, smooth and hyaline,
content not distinctive in either KOH or Melzer's. Cheilocystidia of two types:
clavate to saccate and 18-38x 10-18 /A, and smaller than the pleurocystidia but
approximately the same shape and otherwise as described above. Caulocystidia
versiform, smooth thin-walled, content not distinctive.
Gill trama regular, hyaline to faintly brownish in KOH, the hyphae more or
less parallel and with broad (10 / or more) hyphal cells. Pileus having a cuticle
of vesiculose and pear-shaped cells intermingled, the layer one cell deep but not
organized into a true palisade, the cells with thin, hyaline and smooth walls and
the content not distinctive in either KOH or Melzer's. Hyphae of the trama interwoven, the walls tinged rusty vinaceous in KOH but soon fading to brownish or
nearly hyaline, smooth or practically so. Clamps present. No distinctive reaction
on any tissue when mounted in Melzer's.
Type locality. Near Manchester, Michigan.
Habit and habitat. Scattered to gregarious on rich humus and debris, May.
Distribution. Michigan.
Observations. This species was previously identified as P. spadiceogrisea
(Smith, 1941), but the current concept of the latter in Europe calls for utriform
pleurocystidia.
Material examined. Michigan: Ammirati 1543, 1547, 2926; Harding &
Belizzi 4-29-51; Hoseney 1520; Potter 7121, 9427, 9581; Smith 6207 (Type), 6221,
6228, 15016, 18036, 20294, 20347, 20354, 28615, 28637, 28670, 28673, 28674, 32296,
34285, 36515, 41319, 41426, 49531, 73023, 74374, 4-21-51, 4-27-52.
133. Psathyrella alnicola A. H. Smith, sp. nov.
Pileus 2-6 cm latus, late conicus, vel convexus, cinnamomeo-brunneae, ad
marginem appendiculatus; lamellae pallidae demum fumoso-brunneae, confertae,
angustae demum latae; stipes (4-)8-15 cm longus, (3-)4-6 mm crassus, 6-8 mm
ad basem, deorsum sordide melleus, rare annulatus (velum submembranaceum);
sporae 8-11x5-6 f; pleurocystidia 42-64x10-18,u, fusoide ventricosa, obtusa
vel acuta; fibulae adsunt. Typus. Smith 70222 (MICH); legit prope Warren,
Idaho.
Illust. Text Figs. 300-302.
Pileus 2-6 cm broad, obtusely conic to convex, expanding to broadly conic,
surface glabrous, cinnamon-brown when moist, pale dingy tan ("cinnamon-buff")
when faded, when moist the margin faintly striatulate, margin at first appendicu