The North American species of Psathyrella.

1972]

PSATHYRELLA

233

(7-) 8-10 x5-6,u (12X 7.5 u); pleurocystidia 32-46x 10-16 [k, ventricosa, obtusa;
fibulae adsunt. Typus. Smith 20414 (MICH); legit prope Highland, Michigan.
Illust. P1. 64, fig. a; Text Figs. 435-439.
Pileus 1-2.5 cm broad, obtusely conic becoming broadly campanulate or
expanded umbonate, chocolate-brown moist and surface more or less covered
with white appressed superfical fibrils, glabrescent, hygrophanous, fading to pale
tan ("cinnamon-buff") on the disc and darker alutaceous in age, the margin paler
but retaining a cinnamon-buff tinge, rugulose when faded. Context when moist
brownish, pallid when faded, very thin and fragile, odor and taste not distinctive.
Lamellae dull brown becoming drab (no red tones present), horizontally
adnate, broad (3.5 mm), close to nearly subdistant, edges fimbriate.
Stipe 1-3(-4) cm long, 1-1.5(-2) mm thick at apex, whitish or soon tinged
sordid brownish but no distinct color change evident, soon glabrous, the veil
remnants white and at first forming a thin layer breaking into appressed patches,
fragile and hollow.
Spores (7-)8-10x5-6, or rarely 12x7.5 /, smooth, pore apical to oblique
and apex not truncate, shape in face view strongly ovate to elliptic, in profile ovate
to elliptic, color in KOH dark bister, in Melzer's tawny-red, wall about 0.3 pu thick.
Basidia 4-spored, 18-24 x7-9 /, elliptic-pedicellate to clavate, hyaline in
KOH. Pleurocystidia 32-46 x 10-16 i, abruptly ventricose with a neck 4-6 u wide
ending in an obtuse apex, wall thin, smooth and hyaline, content not distinctive
in either KOH or Melzer's. Cheilocystidia clavate to vesiculose, 18-30 x 9-15 j,
hyaline or with faintly yellowish pedicels. Caulocystidia similar to pleurocystidia
varying to clavate, smooth, thin-walled and hyaline.
Pileus with a cuticle of vesiculose cells in more or less of a palisade 1-2 cells
deep, the walls thin, smooth and hyaline, the cells' content not distinctive in KOH
or Melzer's, or the pedicels of some with slightly brownish walls. Hyphae of the
trama ochraceous as revived in KOH and with incrusting material, yellowish in
Melzer's. Clamp connections present.
Type locality. Highland, Michigan.
Habit and habitat. Gregarious to scattered on wet leaves and moss in a swamp.
Distribution. Michigan.
Observations. The spores are medium sized for Psathyrella and distinct
because many have an oblique germ pore and the spore apex does not appear
truncate.
Material examined. Michigan: Smith 20414 (Type), 33742.
191. Psathyrella fibrillosa (Fries ex Persoon) Maire in Maire & Werner, Mem.
Soc. Sci. Nat. Maroc 45: 113. 1937.
Agaricus fibrillosus Fries, Syst. Mycol. 1: 297. 1821.
Psathyra fibrillosa (Fr.) Kummer, Fiihr. Pilzk. 70. 1871.
Drosophila fibrillosa (Fr.) Quelet, Enchir. Fung. 117. 1886.
Illust. P1. 64, fig. b; P1. 69, fig. b; Text Figs. 440, 441.
Pileus (1.5-)2-3.5 cm broad, obtuse becoming campanulate and finally convex
to nearly plane, or with a slight umbo, surface at first covered with small fascicles
of whitish fibrils, soon glabrous, hygrophanous, when moist "buckthorn brown"
to "cinnamon-brown" (honey brown to cinnamon-brown), fading to grayish
cinnamon-buff to pallid, slightly striate when moist. Context thin, brownish when
moist, pallid faded, odor and taste not distinctive.