The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

occasionally with faint bluish stains in older specimens. Odor not distinctive.
Taste pleasant to slightly bitter. Context about 5 mm or less thick at the stipe,
pale buff, unchanging.
Lamellae pallid becoming grayish brown and finally reddish, close, broad,
adnate, edges even,
Stipe 3-10 cm long, 3-15 mm thick at apex, tapering downward slightly, curved
to flexuous, fibrillose-stuffed, becoming hollow; surface with a detersile furfuraceous to squamulose covering from apex to midportion (at least), fibrillose-striate
near apex, surface light buff with white ornamentation, interior white to buff,
unchanging except in extreme base when stipe is torn longitudinally, first becoming deep purplish red in a small area but soon vinaceous over a larger area
(spreading from the spot of the original change).
Spore deposit brick red when moist, dark vinaceous red as dried. Spores
9-11 x 4.5-6 /, smooth, apex with a minute hyaline spot (under oil) but apex not
truncate, shape in face view elliptic to ovate, in profile obscurely bean-shaped to
obscurely inequilateral, color in KOH vinaceous-hyaline, not much darker in
Melzer's (not cocoa-brown in KOH and not becoming darker on standing).
Basidia 4-spored, 20-30 x 6-8 ga, narrowly clavate, hyaline in KOH. Basidioles
narrowly clavate. Pleurocystidia 43-56x13-17 g, broadly fusoid to ventricosefusoid, smooth or apex incrusted (revived in KOH) in a few, wall thickened
somewhat at least near or in the apex (up to 1.5-2 I4), hyaline in KOH and
Melzer's. Cheilocystidia versiform, (1) fusoid and about like the pleurocystidia
but up to 60 x 10-14 / (longer and narrower); (2) fusoid-ventricose with obtuse
apex varying to utriform, 42-50x 10-15,, thin-walled, smooth; (3) clavate to
saccate, hyaline thin-walled, 20-35 x 9-15 g. Caulocystidia mostly large, inflated,
versiform thin-walled cells or some shaped about like the pleurocystidia but with
thinner walls, all extremely variable in size.
Gill trama regular, cells long and inflated near the subhymenium, brownish
in KOH; subhymenium very narrow and of compactly interwoven hyphae. Pileus
cuticle a staggered palisade of clavate to pyriform cells with vesiculose cells
intermingled, all hyaline and thin-walled. Trama proper of hyaline interwoven
hyphae. Clamp connections present.
Habit, habitat and distribution. Cespitose on a basswood stump, Wheeling
Township, Rice County, Minnesota near Nerstrand Woods State Park, August 6,
1971, collected by Dr. H. E. Calkins, Mrs. M. G. Weaver no. 2204 (MICH).
Observations. This species resembles P. variata to some extent macroscopically, but is at once distinguished by its broad gills and red stains at the base of
the stipe. The latter did not appear to be of bacterial origin. Microscopically it
is distinguished by having only lamprocystidia in the hymenium. Psathyrella
sublateritia has the peculiar elongated caulocystidia.
(See) 161. Psathyrella salictaria (variant Smith 81028)
Pileus 15-20 mm wide at base, 2 cm high, obtusely conic, at first with a thin
outer veil breaking into scattered inconspicuous squamules, margin slightly appendiculate at first, soon glabrescent overall, color near "snuff brown" fading to
grayish buff. Context thin and fragile.
Lamellae grayish buff becoming near "wood brown," close, broad, ascendingadnate.
Stipe 4-5 cm long, 2 mm thick, dingy pallid overall beneath a thin whitish
evanescent fibrillose coating, apex pallid pruinose, not darkened appreciably at
the base.