The North American species of Psathyrella.

19T72

PSATHYRELLA

275

30-47x 10-18 u, utriform, smooth, walls thin and hyaline to slightly yellowish
(in KOH), varying to fusoid-ventricose with obtuse apex and hyaline or yellowish
at base of pedicel, content not distinctive. Caulocystidia 26-48x 10-16 u, utriform clavate, bulbous-rostrate or fusoid-ventricose, apex obtuse to rounded,
hyaline, thin-walled, content not distinctive.
Pileus cuticle of inflated cells 15-30 p wide, with hyaline to ochraceous walls
in KOH, from the layer extend rusty brown, thick-walled setae up to 250 / long
(but usually broken and found in shorter pieces), the walls 1.5-2.5 / thick, base
at times 7-11 u thick,, neck 5-7 /x, outer surface rarely with slight incrustations.
Hyphae of subcuticular zone ochraceous-tawny in KOH and with fine pigment
incrustations, the color fading. Clamp connections present. No amyloid reactions
present on any tissue.
Type locality. France.
Habit and habitat. Cespitose on rotten wood and on humus under Populus
species in North America. Spring and early summer.
Distribution. Alaska, Idaho, New Mexico, Utah and Wyoming.
Observations. Psathyrella conopilea is solitary to gregarious often in garden
soil. The pileus is not sulcate-striate. Benoist's species is associated with aspen
wood in the western states and occurs in large clusters. Benoist found it with oak.
It is interesting to note that this fungus, apparently very rare in Europe, is
actually one of the common species in the aspen area of our western mountains.
Material examined. Alaska: Wells-Kempton 7-24-65 no. 5. Idaho: Smith
58533. New Mexico: Barrows 68, 868. Utah: McKnight F 433, F 360, F 360a,
F 977; Solheim 4278, 4279. Wyoming: Solheim 3489, 4137, 4167, 4748, 4758, 4771.
234a. Psathyrella circellatipes var. microspora A. H. Smith, var. nov.
Pileus 1-3 cm latus, conicus vel campanulatus, glaber, interdum ad marginem
sparse luteo fibrillosus, castaneus; lamellae cinnamomeae demum fusco-brunneae,
confertae demum latae; stipes 4-8 cm longus, 1-2.5 mm crassus, glaber sed ad
basem fibrillosus; sporae 10-12 x 5-6 x6.5-8 I; cheilocystidia 36-50x 10-16 pI,
versiformia; fibulae adsunt. Typus. Smith 35326 (MICH); legit prope Laramie,
Wyoming.
Pileus 1-3 cm broad, obtusely conic expanding to broadly conic or campanulate, at times nearly convex, glabrous, under a lens scattered brown hairs (setae)
visible, at times with the remains of the thin yellow veil along the margin,
lubricous to subviscid, moist, hygrophanous and soon fading, "chestnut-brown"
but becoming cinnamon-brown to ochraceous-tawny before fading to cinnamonbuff or pinkish buff, translucent striate in age before fading (not plicate), very
atomate when faded. Context thin and exceedingly fragile, odor and taste not
distinctive.
Lamellae pale dull cinnamon when young, chocolate-color at maturity, close,
narrow to moderately broad, adnate and readily seceding, edges even and scarcely
whitish.
Stipe 4-8 cm long, 1-2.5 mm thick, equal or nearly so, perfectly glabrous over
all except at the extreme base which typically is dotted with orange-yellow
fibrillose flecks from a rudimentary partial veil.
Spores 10-12x5-6.5x6.5-8 a/, compressed slightly, apical pore present but
apex not distinctly truncate, color "mummy brown" to black in KOH, in Melzer's
dark reddish brown, shape in face view ovate to elliptic, in profile somewhat to