The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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mummy brown in KOH (but many pale spores present), rusty brown to bay in
Melzer's.
Basidia 4-spored. Basidioles clavate. Pleurocystidia 50-75 x 10-15,u, fusoidventricose with a long pedicel and long, tapered neck to a subacute apex, hyaline,
thin-walled, smooth. Cheilocystidia basically similar to pleurocystidia but smaller
and some hyaline, clavate cells also present.
Gill trama of hyaline inflated cells; subhymenium "cellular" but present only
as a narrow zone 1-2 cells deep. Pileus cuticle a layer of cells 3-4 deep, with
hyaline walls. Subcutis hyaline or nearly so in KOH. Clamps present.
Habit, habitat and distribution. Scattered to gregarious on chip dirt, Ann
Arbor, Michigan, October 12, 1971, Mrs. Carol Nimke 158.
Observations. The worm-like, rooting, strigose base, the long pleurocystidia,
the shiny appearance of the pileus and the grayish lilac state (near maturity) of
the gills along with the white stipe and lack of a veil are its distinguishing
characters. Ample specimens have been available for study and no tendency
toward staining or flushing pink after loss of moisture was noted. It is close to
P. microrhiza sensu Van Waveren (1971, p. 267), but the original concept of
P. microrhiza calls for a pileus "luteo piloso," a term in no way applicable to the
American collections.
406. Psathyrella olivaceocystis A. H. Smith, sp. nov.
Pileus 3-5 cm latus, circa 4 cm altus, glaber, melleobrunneus, deinde pallide
subochraceus, levis, firmus; lamellae pallidae demum ochroleucae demum griseobrunneae, confertae, angustae, ad acierum pallidae; stipes 5-7 cm longus,
3-4.5 mm crassus, firmus, albidus vel pallidus, glaber; sporae 6.5-7.5x 3.5-4 i/;
pleurocystidia 36-52 (-62) x 8-12x 3-4.5 u, fusoide ventricosa, subacuta, cum
"KOH" intus olivacea; cheilocystidia 32-56 (-70) x 9-13x 3-4.5 A, cum "KOH"
intus olivacea. Typus. legit W. Patrick, in Ann Arbor Michigan, 19 Oct., 1971,
ad terram (MICH).
Pileus 3-5 cm broad across the base, obtusely conic and up to 4 cm high,
surface glabrous, moist and hygrophanous, pale honey-tan when moist, fading
to pinkish buff, very smooth both when moist and when faded, (not at all
atomate), margin even and lacking evidence of a veil. Context watery buff
fading to pallid, firm, odor and taste not distinctive; FeSO, no reaction; KOH,
no reaction.
Lamellae pallid becoming dingy ochroleucous and finally near hair brown,
close, narrow to moderately broad, ascending-adnate, edges pallid.
Stipe 5-7 cm long, 3-4.5 mm thick, equal down to a slightly bulbous base,
rather firm, dull white throughout and overall, naked, apical third faintly pruinose,
no discolorations showing from handling.
Spores 6.5-7.5 x 3.5-4 /, smooth, apex in many slightly truncate from a small
pore, shape in face view oblong to slightly ovate, in profile subelliptic to obscurely
bean-shaped or obscurely inequilateral, color cocoa-color in KOH but quickly
becoming dark chocolate color.
Basidia up to 8, broad, clavate. Basidioles clavate. Pleurocystidia very rare,
36-52 (-62) x 8-12 x 3-4.5 g, subacute, base ventricose, neck often flexuous, many
with pale olive content in KOH (when fresh), rarely with olive areas in the
hymenium (including some basidia). Cheilocystidia 32-56 (-70) x 9-13 x 3-4.5 /j,
many with olive content in KOH fresh, smooth, thin-walled. Caulocystidia
similar to cheilocystidia or longer, many with olive content in KOH.