The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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not distinctive in either KOH or Melzer's. Caulocystidia present merely as
scattered clavate cells near the apex of the stipe.
Pileus cuticle of vesiculose cells arranged in a layer several deep, the cell
walls smooth, hyaline and thin, the cell content not distinctive in either KOH
or Melzer's. Hyphae of the trama floccose, interwoven, hyaline or nearly so in
mature pilei. No distinctive reactions present on material revived in Melzer's.
Clamp connections present.
Type locality. Cleveland, Ohio.
Habit and habitat. Clustered on hardwood stumps, etc.
Distribution. Michigan and Ohio.
Observations. This species is at once distinguished from P. candolleana
by the larger spores. It has the appearance of basidiocarps so often referred
to "Hypholoma appendiculatum," but the use of that name is certainly not
justified for this American Psathyrella. The latter resembles P. huronensis
in stature but is distinguished by its caulocystidia and more highly colored pileus.
Material examined. Michigan: Smith 15514, 33690, 33950, 34080, 38764. Ohio:
Walters 4 (Type).
60. Psathyrella uliginicola McKnight & A. H. Smith, sp. nov.
Pileus 5-10 cm latus, obtusus vel hemisphericus demum late expansus, dilute
griseus, subsericeus, ad marginem sparse appendiculatus; lamellae adnatae 5-6
mm latae, confertae, pallidae demum vinaceo-brunneae; stipes 8-12 cm longus,
12-15 mm crassus, albus, sericeus, deorsum tactu dilute brunneae; sporae 10-15 x
5-6 1; fibulae adsunt. Typus. Smith 34903 (MICH); legit prope Laramie,
Wyoming.
Illust. Pls. 31, 32; Text Figs. 154-156.
Pileus 5-10 cm broad, globose when young, the margin incurved, becoming
hemispheric to broadly convex, finally plane or obtusely umbonate, pallid to
grayish, subhygrophanous "avellaneous" or "wood brown" when moist, surface
with a faintly silky appearance due to scattered appressed fibrils, when young
with scattered fibrils near the margin left by a very rudimentary outer veil,
margin at first slightly appendiculate from the remains of a thin but submembranous partial veil, fading to pale avellaneous and in age sometimes slightly
sulcate along the margin. Context firm but brittle, pale drab ("pallid Quaker
drab"), scarcely fading and when bruised darkening somewhat, odor and taste
not distinctive.
Lamellae narrowly adnate, narrow, 5-6 mm broad, crowded to close, thin,
pallid at first, finally dark vinaceous-brown ("army brown"), edges whitecrenulate.
Stipe 8-12 cm long, 12-15 mm thick, equal, hollow, rigid and brittle, white
or whitish, silky beneath the scattered fibrils left by the veil, becoming longitudinally rimose-sulcate in age, white mycelioid at the base, lower portion discoloring
when handled.
Spores 10-12(-15) x 5-6 /, smooth, apical pore rather inconspicuous, shape in
face view elliptic to oblong, in profile more or less bean-shaped, in KOH sordid
cinnamon to pale cocoa-color but soon with a dark-chocolate cast, in Melzer's
tawny, wall about 0.3 j thick.
Basidia 28-33 x 10-12 /, 4-spored, hyaline in KOH, clavate. Pleurocystidia
not differentiated. Cheilocystidia abundant, of two types: (1) 45-70 x 10-16,u,
elongate-utriform to cylindric, wall hyaline, smooth and thin, content not distinctive; (2) 10-16 x 8-12 /, vesiculose to clavate, hyaline and thin-walled.