The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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margin conspicuously appendiculate with a white fringe; context thick, white,
unchanging, taste sweet and nutty.
Lamellae broadly adnate with a slight notch, several times inserted, medium
close, quite broad, the edges densely fringed with cheilocystidia.
Stipe about 2 cm long, 2-4 mm thick, equal or subequal, smooth, glabrous,
white above, floccose and yellowish below, fistulose, pallid within.
Spores 7-7.5 x 4-4.5 t, smooth, germ pore apical but inconspicuous under oil,
cocoa-brown in KOH, slowly darker, bright fulvous in Melzer's; ellipsoid to
slightly ovoid.
Basidia 4-spored, 8-9 / broad. Pleurocystidia none. Cheilocystidia scattered,
22-34 x 9-13 u, fusoid-ventricose with scarcely any neck and an obtuse to subacute apex, smooth, thin-walled, content not distinctive in KOH or Melzer's,
clavate to subvesiculose cells also present.
Cuticle of pileus a layer of vesiculose cells 2-5 deep with a fair number disarticulating in KOH mounts (sphaerocyst-like), walls thin and yellowish to hyaline. Subcutis of cocoa-brown hyphae in KOH and some incrustations present.
Context of interwoven hyaline hyphae with inflated cells. Clamps present.
Habit, habitat and distribution. The specimen studied was sent me by
W. A. Murrill and labeled from the type locality, but no date was given. In the
original description it was described as growing on bare ground in Gainesville,
Fla., May 31, 1938 (F-16227).
Observations. On the basis of the original description and the specimen studied
this species appears to be in the Candolleanae of this work in all features except
that of the disarticulation of some of the cuticular elements. Because of this
feature the species is tentatively placed in Cystopsathyra.
403. Psathyrella grasmerensis Trueblood & A. H. Smith, sp. nov.
Pileus 3-4.5 cm latus, plano-umbonatus, pallide fulvus, udus, striatus, ad
marginem tenuiter fibrillosus, glabrescens, fragilis; lamellae adnatae, distantes,
latae, pallide brunneae demum rufofuscae; stipes 7-8.5 cm longus, 3-5 mm crassus,
albidus, nitens; sporae 8-10x4.5-5.5 I; pleurocystidia 35-60x12-20(-30) /,
obtusata, intus ad apicerum cum granis hyalinibus. Typus. E. Trueblood 3543
(MICH); legit prope Grasmere, Owyhee County, Idaho, 21 Mai, 1970. ad terram.
Pileus 3-4.5 cm wide when expanded, plane with a low umbo, when moist
striate from umbo to the margin, tan or darker when moist, pale tan when dried,
margin decorated with a coating of veil fibrils, becoming glabrous. Context very
thin, odor and taste not distinctive.
Lamellae adnate, distant, broad, rarely forked, pale brownish becoming
reddish fuscous, as dried chocolate color.
Stipe 7-8.5 cm long, 3-5 mm thick, straight to flexuous, shining white, silky,
dingy buff as dried.
Spores 8-10x4.5-5.5 g, smooth, with a broad hyaline lens-shaped pore (but
apex not truncate), oblong to elliptic in face view, in profile oblong to subelliptic,
color as revived in KOH dark chocolate-color very soon, wall about 0.3,/ thick.
Basidia 4-spored. Brachybasidioles not differentiated. Pleurocystidia 35-60 x
12-20(-30) /, broadly ventricose and mostly with a short neck arising abruptly
from the ventricose portion (rostrate), the neck (or necks, since some branch into
2 or 3 projections) 5-7 g wide, the apex obtuse and refractive granules usually