The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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187. Psathyrella laurentiana A. H. Smith, sp. nov.
Pileus 10-15 mm latus, convexus vel late convexus, albo-floccosus, glabrescens,
cinnamomeo-brunneus; lamellae sordide cinnamomeae demum violaceo-griseae;
angustae, confertae; stipes 3-4 cm longus, circa 1 mm crassus, albidus, fibrillosus,
glabrescens; sporae 8-10 x 4-5 /; pleurocystidia 44-66 x 10-16 A, fusoide ventricosa ad apicerum obtusa vel subacuta; fibulae adsunt. Typus. Smith 61654
(MICH); legit prope Le Gite, Quebec, Canada.
Illust. Text Figs. 425-427.
Pileus 10-15 mm broad, convex to broadly convex, margin appressed at first,
surface at first covered with a white fibrillose veil which breaks up into squamules
and disappears, margin fringed in young stages, surface moist and hygrophanous,
cinnamon-brown fading to dingy tan but in drying becoming cinnamon-brown
again. Context very thin and fragile.
Lamellae dingy dull cinnamon becoming violaceous-drab by maturity but
drying about concolorous with pileus, narrow, close, adnate-seceding, edges even.
Stipe 3-4 cm long, about 1 mm thick, equal, white, unchanging, at first with
veil fibrils variously dispersed over lower half, glabrescent, pruinose above.
Spores 8-10 x 4-5 u, smooth, apical pore distinct and apex somewhat truncate,
shape in face view narrowly to broadly ovate, in profile obscurely inequilateral to
somewhat so, varying to subelliptic, color in KOH chocolate-brown becoming
chocolate-gray, in Melzer's reddish tawny, wall about 0.3 / thick.
Basidia 4-spored, short-clavate, 17-23 x 8-9 /, hyaline. Brachybasidioles present at maturity (about 10,t wide), an occasional one seen with 1-5 echinulate
processes over the upper half. Pleurocystidia abundant, 44-66 x 10-16 /, fusoidventricose with obtuse to subacute apex, when first revived with granular material
adhering around and over the apex, and the walls hyaline and thin, on standing
for 5 minutes or so in KOH the wall in many of the cystidia swelling slightly to
0.3-0.4,/ thick and becoming weakly ochraceous. Cheilocystidia varying from
similar to pleurocystidia to clavate or vesiculose, hyaline to yellowish in KOH,
walls thin and smooth. Pileus cuticle a layer of inflated cells about 2 deep, the
walls thin and smooth, weakly ochraceous to hyaline in KOH. Hyphae of the
context brownish when first revived in KOH, walls smooth or practically so.
Clamp connections present.
Type locality. Le Gite, Laurentide Provincial Park, Quebec, Canada.
Habit and habitat. Solitary on Sphagnum in bogs, August.
Distribution. Known only from type locality.
Observations. This species differs from P. sphagnicola in lacking a membranous veil, and from P. borealis in having a well developed fibrillose outer veil,
as well as pleurocystidia some of which develop ochraceous tints in the wall in
KOH. To date it has been found only one basidiocarp at a time.
188. Psathyrella senex (Peck) A. H. Smith, comb. nov.
Psilocybe senex Peck, Rep. N. Y. State Mus. 41: 70. 1888.
Illust. Text Figs. 428, 429.
Pileus 1-3 cm broad, hemispheric to convex or occasionally obtuse, the margin
incurved slightly at first but soon straight, broadly convex in age, surface glabrous
over the disc when mature but toward the margin usually with small fascicles of
whitish fibrils from the remains of the outer veil, the margin at times fringed
slightly but usually glabrous in age, moist and hygrophanous, more or less