The North American species of Psathyrella.

1972]

PSATHYRELLA

239

hyphae of the central area also colored in KOH at least in age but the layer
not appearing dark colored because of the width of the cells.
Cuticle of pileus of vesiculose cells in a layer 2-3 cells deep, the walls more
or less refractive and up to 0.5 E/ thick in some, smooth, cell content not distinctive.
Hyphae of subcutis colored like those of the gill trama, no incrustations clearly
visible. Clamp connections present.
Type locality. Priest Lake, Idaho.
Habit and habitat. Subcespitose on a cottonwood log, October.
Distribution. Known only from the type locality.
Observations. The stature is that of P. conissans, the caulocystidia are most
like those of P. sublateritia, and the spore color is closest to that of P. spadicea.
This species appears worthy of placing on record for a number of reasons,
but to me the most important one is the complete progression from leptocystidia
to lamprocystidia on single pilei. This progression was demonstrated on mature
pilei where the age of the cell could not be questioned. In this species the
lamprocystidia become about as large as is known for the genus. If one were
to postulate that higher fungi hybridize, this species could be cited as a good
example of such a possible hybrid.
197. Psathyrella littenii A.H. Smith. sp. nov.
Pileus 3.5-5 cm latus, late convexus, pallidus vel brunneolus, demum cacaocolor; velum nullum; lamellae perangustae, confertae, brunneolae demum vinaceorufae; stipes 3-5 cm longus, 3-6 mm crassus, glaber, pallidus, ad basem myceliosus; sporae 7-8.5x (3.5-) 4-4.5 t; pleurocystidia 32-43x8-16 I, ovatomucronata, maura 0.6-3 p crasso; fibulae adsunt. Typus. Litten 8-27-67
(MICH); legit prope Hulbert, Michigan.
Illust. Text Figs. 453-455.
Pileus 3.5-5 cm broad, convex with an inrolled margin, expanding to broadly
convex or nearly plane, pallid to brownish when young, becoming reddish cocoacolor as the spores mature, glabrous, moist and hygrophanous. Context thin and
subcartilaginous, brownish fading to pallid brownish, odor not distinctive.
Lamellae very narrow and crowded, adnate but soon seceding, pallid brownish
but soon becoming dull reddish vinaceous and strongly vinaceous-red as dried,
edges fimbriate in age.
Stipe 3-5 cm long, 3-6 mm thick, equal or nearly so, subcartilaginous, tubular,
base slightly mycelioid, surface pruinose above, naked below, veil absent.
Spore deposit (on stipe) dull red. Spores 7-8.5 x (3.5-)4-4.5 /, smooth, apical
pore absent (for any practical purpose), shape in face view ovate to elliptic, in
profile obscurely bean-shaped to obscurely inequilateral, color in KOH hyaline
with a pinkish reflection, in Melzer's nearly hyaline, wall about 0.3 u thick.
Basidia 4-spored, 17-22 x 6-7 p, clavate, hyaline in KOH in well dried material. Pleurocystidia 32-43x8-16 A, ovate-mucronate with wall in neck 0.6-3 /
thick, apex incrusted at first, content often distinctive by way of numerous
isodiametric masses of highly refractive material 2-5 p diam or in some these
often adhering to inner surface of the wall (as revived in KOH). Cheilocystidia
30-65 x 10-25 I, subelliptic, utriform, clavate, or ventricose with rounded apex,
thin-walled, content not distinctive, wall hyaline to yellowish in KOH. Caulocystidia mostly clavate to inflated variously (vesiculose, utriform, etc.) but generally like the cheilocystidia.
Gill trama snuff brown in the zone next to the subhymenium; subhymenium