The North American species of Psathyrella.

1972]

PSATHYRELLA

177

late with remains of the submembranous veil. Context very thin and fragile, odor
and taste not distinctive, with FeSO4 no color change.
Lamellae pallid at first then very soon pale dull brown, at maturity violaceousfuscous, narrow to moderately broad, close, adnate but soon seceding, edges even
and whitish.
Stipe (4-)8-15 cm long, (3-)4-6 mm at apex, 6-8 mm below, gradually
thickened slightly, white, by maturity or in age becoming dingy honey-color over
the basal area, surface thinly fibrillose to the silky-punctate apical region; veil
pallid, submembranous, rarely forming an incomplete annulus.
Spores 8-11 x 5-6 a, smooth, with a hyaline spot at apex but apex rounded,
shape in face view ovate to elliptic, the apiculate end (base) often obscurely to
distinctly truncated, a few showing a slight degree of angularity, in profile elliptic
to obscurely inequilateral, color in KOH dark rusty brown with a smoky tinge,
slowly becoming dark chocolate-color, in Melzer's reddish tawny; wall about
0.4 j thick.
Basidia 25-32x8-11 g, 4-spored, hyaline in KOH. Pleurocystidia 42-64 X
10-18 g, broadly fusoid with obtuse apex, fusoid-ventricose with obtuse to subacute apex, and a few utriform to cylindric-pedicellate, all smooth, thin and
hyaline, content of cell not distinctive in either KOH or Melzer's. Cheilocystidia
32-35x9-14 a, fusoid-ventricose, hyaline, rare to scattered, many clavate to
vesiculose cells also present and hyaline to yellow in KOH, pigment in the wall.
Caulocystidia very rare, the only ones seen were clavate to vesiculose and 9-15.
wide.
Pileus with a cuticle of vesiculose and clavate cells mixed and 2-3 cells deep,
walls hyaline in KOH, smooth, thin, cell content not distinctive in either KOH
or in Melzer's. Hyphae of trama in subcuticular region especially dull cinnamon
in KOH but fading on standing, the walls smooth or obscurely uneven. Clamps
present. No distinctive reaction on any tissue when revived in Melzer's.
Type locality. Warren, Idaho.
Habit and habitat. Gregarious under alder on soil.
Distribution. Idaho.
Observations. The distinctive features of this species are the broad often somewhat truncate (basally) spores, pleurocystidia varying from fusoid-ventricose to
utriform, the long stipe and apparent lack of any distinctive caulocystidia.
Material examined. Idaho: Smith 70222 (Type); Trueblood 162, 1439, 1458,
2280, 2680.
134. Psathyrella mesocystis A. H. Smith, sp. nov.
Pileus 3-3.5 cm latus, plano-umbonatus, glaber, ad marginem appendiculatus,
cinnamomeo-brunneus; lamellae confertae, latae, fumoso-brunneae; stipes 4-5 cm
longus, 3-4 mm crassus, glaber, pallidus; sporae 7-9 x4-4.6 I; pleurocystidia
42-63 x 9-15 g, fusoide ventricosa, subacuta; cheilocystidia clavate vel vesiculosa;
fibulae adsunt. Typus. Smith 65274 (MICH); legit prope McCall, Idaho.
Pileus 3-3.5 cm broad, plano-umbonate, glabrous, margin at first appendiculate from patches of the submembranous veil, hygrophanous, near cinnamonbrown when moist, fading to dingy pinkish buff on disc (pale dull tan) and pale
vinaceous-buff (having a pinkish flush) toward the margin, dull cinnamon when
dried. Context pallid, firm, odor and taste not distinctive, with either KOH or
FeSO4 no reaction.