The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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a few vesiculose. Caulocystidia scattered, more or less similar to the pleurocystidia
but usually smaller.
Gill trama of hyaline interwoven hyphae in water mounts of fresh material,
slightly brownish as revived in KOH. Pileus trama faintly brownish in water
mounts of fresh material and dingy yellowish brown (near "bister") when revived
in KOH, pigment incrusted on the hyphae at least in the subcuticular region.
Cuticle of pileus a thin layer I cell thick of clavate-pedicellate cells mixed with
vesiculose elements, the walls thin, smooth and hyaline, cell content not distinctive. Clamp connections present.
Type locality. On the old Barlow Trail, Mt. Hood, Oregon.
Habit and habitat. Gregarious on alder debris, October.
Distribution. Michigan, Oregon.
Observations. The veil is better developed than in P. duplicata, the pleurocystidia are distinctly narrower, and pink tints do not develop in age.
Material examined. Michigan: Smith 25309, 25310. Oregon: Smith 24284
(Type), 24286.
286. Psathyrella thujina A. H. Smith, sp. nov.
Pileus 1-2 cm latus, convexus vel campanulatus, glaber, cinnamomeo-brunneus;
contextu in "FeSO4" olivaceo-griseus; lamellae brunneolae demum sordide cinnamomeae, latae, confertae demum subdistantes; stipes 3-6 cm longus, 1-1.5 mm
crassus, albus, deorsum brunneolus, glaber; velum nullum; sporae 9-12 x 5-6 U;
pleurocystidia 38-56 x 9-15 u, fusoideo-ventricosa, ad apicerum cum 2-3 processis;
fibulae adsunt. Typus. Smith 66720 (MICH); legit prope Burt Lake, Michigan.
Illust. P1. 89, fig. a; Text Figs. 614-617.
Pileus 1-2 cm broad, obtusely conic, expanding to convex or broadly convex
to campanulate, glabrous, moist and hygrophanous, cinnamon-brown fading to
wood brown, faintly striatulate moist, opaque when faded, finally pale tan on the
disc. Context very soft and fragile, pallid brownish, odor and taste mild, FeSO4
causing a change slowly to olivaceous-gray.
Lamellae pallid brownish becoming near Verona brown (dull cinnamon),
broad, close to subdistant, seceding, edges even.
Stipe 3-6 cm long, 1-1.5 mm thick, equal, white to whitish, base only slightly
brownish, no appreciable number of fibrils present; no veil seen.
Spores 9-12 x 5-6 /, smooth, apical pore evident, shape in profile subovate to
obscurely inequilateral, in face view ovate to elliptic, dark chocolate-color, in
Melzer's reddish tawny, wall about 0.3 u thick.
Basidia 4-spored, 9-11 u wide at apex, clavate, hyaline. Pleurocystidia
38-56 x 9-15 uA, ventricose and with a short neck, in the majority the neck branched
into 2-3 finger-like extensions which are obtuse at the apex, wall thin, smooth and
hyaline, content not distinctive. Cheilocystidia vesiculose and up to 10 p wide
(rare) or clavate to subvesiculose-pedicellate and 32-40 x 8-16 M (numerous), and
a few resembling the pleurocystidia, all hyaline smooth and thin-walled. Caulocystidia scattered, resembling the cheilocystidia.
Pileus cuticle 1-2 cells deep, the cells vesiculose, 18-40 M wide, yellowish to
brownish in KOH, walls thin and smooth, cell content not distinctive. Subcuticular region vinaceous-brown in KOH and with incrustations on the wall or
with local wall thickenings especially near the septa. Clamps present. No distinctive reactions on any tissue when revived in Melzer's.
Type locality. North end of Burt Lake, Cheboygan County, Michigan.