The North American species of Psathyrella.

1972]

PSATHYRELLA

169

demum purpureo-fuscae; stipes 3-5 cm longus, 2-3 mm crassus, sparse fibrillosus
pallide brunneus; sporae 7-9.5x 4-5 p; pleurocystidia 34-48x10-16 JA, fusoide
ventricosa, obtusa; fibulae adsunt. Typus. Smith 72497 (MICH); legit prope
Roscommon, Michigan.
Pileus 1-3 cm broad, obtuse expanding to convex or broadly convex, margin
appressed at first and with small fascicles of fibrils representing the remains of
a thin veil often at first denticulate along the margin, soon glabrous over all,
when moist dark honey brown ("buckthorn brown") and fading to pale tan or
more ochraceous but darkening to dingy grayish cinnamon in drying. Context
very thin and delicate.
Lamellae close, adnate, moderately broad, dingy cinnamon becoming purplebrown (near "benzo brown"), dark vinaceous-brown as dried (edges fuscous as
dried).
Stipe 3-5 cm long, 2-3 mm thick, equal, slender, delicate, lower portion
sparsely coated with whitish fibrils, brown beneath, paler and weakly pruinose
above, dull cinnamon over all as dried.
Spores 7-9.5 x4-5,, smooth, truncate because of a small apical pore, shape
in face view elliptic to oval, in profile obscurely inequilateral to subelliptic, color
in KOH dark cinnamon to cocoa-brown soon becoming dark chocolate, in Melzer's
dark reddish tawny, wall about 0.3 p thick.
Basidia 4-spored, 17-22x8-9 /x, hyaline or hymenium flushed cinnamon in
KOH. Pleurocystidia 34-48x 10-16 /u, fusoid-ventricose with obtuse apex, apex
often with granular incrustations, wall thin and hyaline, cell content not distinctive. Cheilocystidia more or less resembling pleurocystidia.
Pileus cuticle a layer of vesiculose hyaline (or nearly so) cells 2-3 deep.
Hyphae of subcuticular zone vinaceous-cinnamon in KOH but incrustations not
conspicuous. Clamp connections present.
Type locality. Houghton Lake, Michigan.
Habit and habitat. Gregarious on sandy soil, September.
Distribution. Known only from the type locality.
Observations. This species features a habitat on rather barren sandy soil, a
thin veil, medium-sized spores, short pleurocystidia, and a darkening stipe. As
for the previous species, it is also keyed out in subsect. Obtusatae of subg.
Psathyrella. The darkening gill edges may be more significant as a taxonomic
feature than I now suspect.
125. Psathyrella fulva A. H. Smith, sp. nov.
Pileus 2-3 cm latus, late conicus, glaber sed ad marginem denticulatoappendiculatus, laete cinnamomeus; lamellae brunneolae, demum violaceo-griseae,
latae, subdistantes; stipes 4-6 cm longus, 2.5-3 mm crassus, fragilis, deorsum
melleus, sursum pallidus, sparse fibrillosus; sporae 8-9(-10) x4.5-5,/; pleurocystidia 42-65 x9-15 /u; fusoide ventricosa; fibulae adsunt. Typus. Smith 73799
(MICH); legit prope Priest Lake, Idaho.
Illust. Text Figs. 286-289.
Pileus 2-3 cm broad, obtusely conic becoming broadly conic, surface glabrous
except for white dentate patches of veil material along the edge at first, color
a rich rusty brown (bright cinnamon to dull tawny), striate nearly to the disc,
fading to pale tan. Context exceedingly fragile, odor and taste not distinctive,
with application of FeSO4 no color change.
Lamellae dull brown when young, becoming wood brown and finally shaded