The North American species of Psathyrella.

160 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [VOL. 24
with flexuous walls and irregular in shape (basically subcylindric), wall thin to
slightly thickened and then refractive and weakly yellow in KOH on standing
5-10 minutes, smooth or with granules over apex and apex tending to remain
collapsed in KOH. Cheilocystidia more or less similar to pleurocystidia (usually
smaller), and also clavate hyaline cells intermingled with them.
Pileus cuticle a layer of vesiculose cells 2-3 deep, the walls thin, smooth and
not distinctively colored in KOH. Hyphae of subcuticular region pale vinaceouscinnamon in KOH, walls smooth or nearly so. Clamps present.
Type locality. Girdwood, Alaska.
Habit and habitat. Gregarious to subcespitose around brush piles of decaying
spruce and hemlock slash, August.
Distribution. Known only from type locality.
Observations. This species is close to P. avellaneifolia, but the cystidia are
not vinaceous-brown in KOH, it grows on conifer debris and the pleurocystidia
have more of a tendency to be granulose over the apical portion (which has a
thinner wall than the remainder of the cell and hence tends to remain collapsed).
In this respect it resembles P. paradoxa.
116. Psathyrella wapinitaensis P. Kempton & A. H. Smith, sp. nov.
Pileus 2-4 cm latus, demum late convexus, glaber, umbrino-cinnamomeus,
ad marginem appendiculatus; lamellae pallidae, demum fusco-brunneae, latae,
confertae; stipes 2-4 cm longus, 2-4 crassus, fragilis, pallidus, deorsum demum
sordide brunneus; sporae 7-9x4.5-5 r/; pleurocystidia 40-70x9-14 /u, fusoide
ventricosa vel anguste fusoidea, acuta; fibulae adsunt. Typus. Smith 28032
(MICH); legit prope Frog Lake, Mt. Hood National Forest, Oregon.
Pileus 2-4 cm broad, obtuse to convex with the margin bent in slightly,
expanding to broadly convex or nearly plane, surface glabrous, moist, hygrophanous, russet to cinnamon-brown when moist fading to dingy tan, but very dark
if rehydrated; margin appendiculate at first with pale patches of veil remnants,
soon glabrescent. Context thin and fragile, concolorous with the surface, odor
none.
Lamellae pallid brownish becoming very dark chocolate-color, close, broad,
adnate seceding, edges even but not white.
Stipe 2-4 cm long, 2-4 mm thick, equal, fragile, pallid above, soon brownish
over basal area, with scattered fibrils at first but soon naked except for pruinose
apex.
Spores 7-9 x 4.5-5 Iu, smooth, apical pore very indistinct and apex lacking any
sign of a truncation, shape in face view elliptic to ovate, in profile obscurely
inequilateral to subovate, color in KOH cocoa-brown when first revived but soon
tawny-olive (paler and more olivaceous and finally darker coffee brown), in
Melzer's reddish tawny, wall about 0.3,u thick.
Basidia 4-spored. Pleurocystidia abundant, 40-70x9-14 I, elongated fusoidventricose with subacute apex, often with coagulated material thinly coating the
apical region, wall thin and hyaline, cell content not distinctive. Cheilocystidia
similar to pleurocystidia but smaller.
Cuticle of pileus of vesiculose cells 2-3 deep, walls brownish to hyaline in
KOH, thin and smooth. Hyphae of pileus context vinaceous-cinnamon but soon
hyaline or nearly so in KOH, not roughened. Clamps present.
Type locality. Frog Lake, Mt. Hood National Forest, Oregon.
Habit and habitat. Subcespitose on conifer logs, October.
Distribution. Alaska, Idaho, Oregon.