The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Observations. A comparison of the above description with that of the type
form will reveal slight differences in a few features but these are here not regarded
as sufficient for the establishment of an additional taxon. As one can readily
understand, on such small delicate rare fungi it is a difficult problem to accumulate
enough data to establish a pattern of variation.
(See) 44. Psathyrella singeri (variant Nimke 98)
Pileus 5-20 mm broad, obtusely conic expanding to plano-umbonate or remaining obtusely conic, margin straight at first, glabrous, moist, hygrophanous, avellaneous to ochraceous-gray fading to pallid, the colors nondescript in both moist
and faded condition, opaque to only faintly striatulate, when faded very atomate.
Context exceedingly thin and delicate, odor and taste not distinctive.
Lamellae narrow and close, adnate then seceding, pallid to grayish and finally
avellaneous to wood brown, very thin, edges even.
Stipe 10-15 (-20) mm long, 0.7-1.5 mm thick, equal, hollow, exceedingly
fragile, naked, pallid over all and not darker at base in old basidiocarps, with
sparse radiating white hairs at point of attachment. Veil absent or possibly
rudimentary.
Spores avellaneous to wood brown in deposit, 7-9 x 4-5.5 g, smooth, wall thin
and apical pore not distinct, in KOH nearly hyaline, in Melzer's slowly slightly
toned dingy tan (color not distinctive), shape in face view ovate to elliptic, in
profile obscurely inequilateral.
Basidia 4-spored, clavate, 15-22 x 8-10 /, very short and wide toward gill edge,
more clavate-pedicellate near pileus, hyaline. Brachybasidioles possibly finally
differentiated. Pleurocystidia none. Cheilocystidia 26-35x 10-13 gA, utriform to
fusoid-ventricose with rounded apex or subellipsoid, hyaline, thin-walled, smooth.
Caulocystidia not found.
Gill trama of inflated cells faintly brownish in water or KOH but quickly
fading to hyaline or nearly so, subhymenium subcellular. Pileus cuticle about
2 cells deep, of inflated to pear-shaped cells nearly hyaline in KOH; walls thin
but where "double" (two walls ~ fused) appearing somewhat refractive and
thicker, subcutis of tubular hyphae and those with inflated cells, cocoa-brown in
KOH but slowly fading, smooth or some incrustations present.
Habit, habitat and distribution. Scattered on sticks and debris in a grassy
area, Ann Arbor, Michigan, June 21, 1971, Mrs. Carol Nimke 98.
Observations. This is an extremely delicate variant with nondescript colors,
subhyaline spores in KOH, and is one of those Psathyrellae in which it is difficult
to distinguish basidioles from brachybasidioles. It differs from the type of the
species in having slightly broader spores, more dingy coloration, and generally
smaller size. Both were present in the same habitat at the same time and maintained their identity. This could be an indication that both should be ranked as
autonomous species.
410. Psathyrella sublongispora A. H. Smith, sp. nov.
Pileus 2.5-4 cm latus, convexus, leviter appendiculatus, demum subplanus,
glabrescens, spadiceus, deinde pallide alutaceus; fragilis; lamellae confertae,
angustae, adnatae, brunneolae demum brunneogriseae; stipes 2-3 cm longus,
3-4 mm crassus, fistulosus, subfirmus, pallidus; velum sparsum; sporae 8.5-11
3.5-4(4.5) /; pleurocystidia nulla. Cheilocystidia 36-52x 10-15 g, utriformia vel