The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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255. Psathyrella cordobaensis A. H. Smith, nom. nov.
Atylospora mexicana Murrill, Mycologia 10: 21. 1918. (non Psathyrella mexicana
Murrill, 1918.)
Psathyra mexicana (Murrill) Murrill, Mycologia 10: 33. 1918.
Pileus about 1 cm broad, convex, not fully expanding, not umbonate, surface
glabrous, smooth, sometimes pitted or reticulate, rugose in dried specimens,
uniformly avellaneous-isabelline, margin paler, thin, entire, not incurved but
deflexed and appressed when young.
Lamellae adnate, arcuate, broad, rather crowded, white to pale avellaneous
and finally purplish brown with white edges.
Stipe 1.5 cm long, 2 mm thick, curved, tapering upward, white, smooth,
glabrous above, with abundant cottony tomentum at the base.
Spores 6-7.5 x 3.8-4.4 g, smooth, apical pore indistinct and apex not truncate,
shape in face view elliptic to oblong, in profile elliptic to obscurely inequilateral,
color in KOH pale avellaneous, becoming somewhat darker (the avellaneous tone
weak and tinged ochraceous at first), in Melzer's pale tawny to reddish tawny,
wall about 0.3 M thick.
Basidia 16-19 x 6-7 /, 4-spored, hyaline in KOH. Pleurocystidia none. Cheilocystidia saccate to ellipsoid, 22-30 9-12 I, hyaline, smooth, very difficult to
revive in the type. Gill trama parallel, hyaline in KOH.
Pileus having a cuticle of pedicellate to saccate or vesiculose cells all intermingled, hyaline in KOH. Hyphae of the context hyaline in KOH. Clamps
present.
Type locality. Motzorongo, near C6rdoba, Mexico.
Habit and habitat. Gregarious to subcespitose on decaying wood.
Distribution. Known only from the type locality.
Observations. The pileus which becomes rugose to pitted, lamellae white
at first and arcuate, the abundant cottony mycelium at the base of the stipe and
the small spores appear distinctive.
256. Psathyrella dichroma (Berkeley & Curtis) A. H. Smith, comb. nov.
Agaricus dichromus Berk. & Curt., Jour. Linn. Soc. 10: 292. 1868.
Psilocybe dichroma (Berk. & Curt.) Saccardo, Sylloge Fung. 5: 1057. 1887.
Pileus 10-12 mm broad, at first conic, expanding to plane, glabrous, yellowish
brown. Context thin.
Lamellae thin, distant, adnexed, fuscous.
Stipe 2.5 cm long, 2-3 mm thick, fistulose, glabrous, white.
Spores 6-7.5 x 4-5, smooth, with an obscure apical hyaline pore, pale
chocolate-brown to dull cinnamon-brown when revived in KOH, soon fading and
becoming very pale grayish brown. Cheilocystidia saccate, 20-26 x 10-15 g,
hyaline and rather badly collapsed. Pileus trama with a cuticle of vesiculose
hyaline cells.
Type locality. Cuba.
Habit and habitat. On rotten wood.
Distribution. Cuba.
Observations. The species is clearly a Psathyrella and should be recognizable
by the distant fuscous gills and lack of a veil. The species needs to be redescribed
from fresh material.