The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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109. Psathyrella utahensis McKnight & A. H. Smith, sp. nov.
Pileus 1.5-3.5 cm latus, late convexus, glaber, ad marginem appendiculatus,
ad centrum alutaceus; lamellae confertae, adnatae, angustae, demum latae; stipes
2-3 cm longus, 2-5 mm crassus, sericeus, albidus, deorsum demum brunneus;
sporae 7-9 x 4-4.5 u; pleurocystidia 36-48 x 10-15 J, ventricoso-rostrata, ad apicerum subacuta; fibulae adsunt. Typus. Kent McKnight F-958 (MICH); legit
prope Mt. Timpanogas, Utah County, Utah.
Pileus 1.5-3.5 cm broad, broadly convex at first, becoming plane at maturity,
glabrous, moist, hygrophanous, margin at first appendiculate with remains of
the veil, color "cinnamon-buff" on disc, near "sepia" elsewhere, fading quickly
to "light buff" (pallid yellowish) and often developing pink tints. Context thin
and fragile, concolorous with surface moist or faded, odor and taste not distinctive.
Lamellae close, adnate, narrow to moderately broad, brownish at first, becoming purplish brown and when dried dark vinaceous-brown, edges concolorous as
dried.
Stipe 2-3 cm long, 2-5 mm thick, equal or nearly so, becoming hollow,
cartilaginous, surface silky-fibrillose, whitish becoming dingy brownish, often
with white floccose mycelium at the base.
Spore print near "benzo brown" (purple-brown); spores 7-9 x 4-4.5,, smooth,
apical pore present but apex not truncate, shape in face view ovate to elliptic, in
profile subelliptic to obscurely inequilateral, color in KOH chocolate-brown but
soon dark chocolate-color then chocolate-gray, in Melzer's bay-red, wall about
0.3 k thick.
Basidia 4-spored, 12-24x6-8 /A, clavate, hyaline. Pleurocystidia scattered,
36-48 x 10-15 J, (ventricose-rostrate), (pedicellate, then abruptly ventricose, the
neck 5-6 ~u thick near ventricose portion and flexuous to an obtuse to subacute
apex), wall thin, smooth and hyaline, cell content not distinctive. Cheilocystidia
inflated-pedicellate to cystidioid, hyaline to ochraceous in KOH, 9-15, wide,
walls thin.
Pileus cuticle 1-2 cells deep, a mixture of clavate and vesiculose cells with
smooth, thin, hyaline walls, cell content not distinctive. Hyphae of subcuticular
region pale dull cinnamon in KOH and smooth or nearly so. Clamp connections
present.
Type locality. Aspen Grove, Utah County, Utah.
Habit and habitat. Gregarious on soil, April.
Distribution. Utah.
Observations. The distinguishing features of the species are the rostrate
pleurocystidia, medium sized spores, rather squatty stature, terrestrial habitat
and the pink tints developing on the faded pileus. The generally pale color of
the moist young pileus may also be important.
110. Psathyrella madeodisca (Peck) A. H. Smith, Contr. Univ. Mich. Herb. 5:
51. 1941.
Agaricus madeodiscus Peck, Ann. Rep. N. Y. State Mus. 38: 88. 1885.
Hypholoma madeodiscum (Pk.) Saccardo, Sylloge Fung. 5: 1039. 1887.
Drosophila madeodisca (Pk.) Murrill, Mycologia 14: 62. 1922.
Illust. Smith, 1. c., pl. 28, figs. 1-5. Text Figs. 267-270.
Pileus 1-4 cm broad, obtuse when young, becoming plane with a low broad
umbo, surface moist and hygrophanous, near "cinnamon" when moist but varying
to duller (near "Sayal brown"), fading to pale dingy tan ("cinnamon-buff") to