The North American species of Psathyrella.

1972]

PSATHYRELLA

165

Spores 8-10x4-5,t, smooth, with an apical hyaline spot as a pore, the apex
not truncate, shape in face view oblong to elliptic, in profile subelliptic, color in
KOH dark cocoa-color slowly becoming almost dark chocolate-color, in Melzer's
reddish tawny, wall about 0.4 I thick.
Basidia (18-) 20-32 x 6-9 Lu, hyaline in KOH, elongate-clavate. Pleurocystidia
(46-) 52-70 x 9-15 Iu, narrowly to broadly fusoid-ventricose tapered to an acute
to subacute (rarely obtuse) apex, with debris or mucilaginous material adhering
over apical region in some, wall thin and hyaline, cell content not distinctive in
KOH or Melzer's. Cheilocystidia 28-42 x 7-12 I, fusoid-ventricose with subacute
to obtuse apex, thin-walled, hyaline. Caulocystidia scattered, versiform, clavate,
mitten-shaped, etc., some with secondary septa, walls thin and hyaline, extremely
variable in size.
Gill trama regular, the cells considerably enlarged, pale to dark cocoa-color
in KOH, pigment mostly in the wall but some in cell sap, subhymenium cellular.
Pileus with a cuticle of irregularly shaped (vesiculose) cells 2-3 deep, some cells
clavate (but no true palisade formed) the walls hyaline or nearly so, some
cinnamon-colored pigment in the lower cells or adhering to the inner face of the
wall. Clamp connections present. No distinctive reaction noted on any tissue
mounted in Melzer's.
Type locality. Near Rhododendron, Clackamas County, Oregon.
Habit and habitat. Gregarious on debris under mixed Thuja and Alnus,
September.
Distribution. Michigan, Oregon, Washington.
Observations. This species appears to be very close to P. fatua of Europe but
differs in having acute to subacute pleurocystidia. It also bears some resemblance
to Hypholoma simile Parker but that species apparently has larger spores and
lacks copious veil remnants.
Material examined. Michigan: Kauffman 6-11-10; Smith 7-4-69. Oregon:
Smith 19652, 19696, 20085, 24457 (Type). Washington: Imshaug 840; Smith 2558,
29323,29824,29922, 29924, 30407, 57605.
122. Psathyrella iterata A. H. Smith, sp. nov.
Pileus 3-8 cm latus, conicus demum campanulatus, demum expansoumbonatus, sparse fibrillosus, glabrescens, ad marginem denticulo-appendiculatus;
umbrino-cinnamomeus; lamellae latae (3-7 mm), confertae, secedentes, pallidae
demum griseo-fuscae; stipes 5-8 cm longus, 3-8 mm crassus, fibrillose floccosus
vel subsquamulosus, glabrescens; albidus; sporae 6-8x 3.5-4.5 IL; pleurocystidia
42-58(-70) x9-14(-17) Iu, fusoide ventricosa, obtusa vel acuta; fibulae adsunt.
Typus. Smith 14143 (MICH); legit prope Olympic National Park, Washington.
var. iterata
Illust. P1. 51; Text Figs. 278-280, 284.
Pileus 3-8 cm broad, obtusely conic and with a slightly incurved margin when
young, becoming conic-campanulate or plane and with an obtuse umbo, occasionally broadly convex, surface sometimes covered when young with a thin coating of superficial white fibrils, usually glabrous except for the white fibrillose
patches adhering in a denticulate pattern along the margin, smooth and "Prout's
brown," "russet" or "cinnamon-brown" when moist, faintly striatulate, hygrophanous, fading to "ochraceous-tawny" on the disc and "tilleul buff" over the marginal area, sometimes "pinkish buff" over all when faded or merely pale avellaneous.
Context moderately thin and fragile, brownish, odor and taste mild.