The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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hyaline or yellowish walls in KOH. Cuticle of pileus a layer of inflated cells
several cells deep, walls thin, smooth and hyaline, cell content not distinctive in
KOH or Melzer's. Tramal hyphae hyaline or nearly so in KOH. Veil hyphae
when revived in KOH with yellow stringy content. No distinctive reactions seen
in any tissue in mounts made in Melzer's. Clamp connections present.
Type locality. Upper Priest Lake, Idaho.
Habit and habitat. Gregarious on a cottonwood log, September, Smith 73674.
Distribution. Known only from Idaho.
Observations. This species is close to P. subamara but has a mild taste, and
larger spores and pleurocystidia. The color of the spores in KOH is a deep yellowbrown shaded olive. This is a peculiar color change for a Psathyrella. In many
respects P. lepidotoides fits the description of Drosophila sylvestris but the original description by Gillet reads more like a species related to P. maculata or
P. lacrymabunda var. aggregata. The size is right for the latter, and Gillet mentions yellow at the base of the stipe. The description of the scales reads more like
that of P. maculata, however. Because I think that D. sylvestris in Europe has
become a too generalized concept, no American material is identified with it. In
P. propinqua the spores are typically somewhat compressed.
16. Psathyrella truncatispora (Murrill) A. H. Smith, comb. nov.
Drosophila truncatispora Murrill, Mycologia 10: 66. 1918.
Illust. Text Figs. 39-40.
Pileus 2.5 cm broad, becoming slightly convex, not quite fully expanding, regular in shape, not umbonate, surface hygrophanous, avellaneous, with pale
isabelline fulvous imbricate floccose scales which are distinct but not conspicuous,
margin entire, concolorous. Context thin and fragile.
Lamellae plane, adnexed, broad, subdistant, avellaneous to pale chestnut.
Stipe 4 cm long, 3 mm thick, short, equal, smooth, white, fragile, hollow.
Spores 6-7x4-5 A, smooth, apex rounded but a hyaline apical pore present,
base more or less truncate as seen in face view, in profile somewhat bean-shaped,
purplish brown in water mounts, pale dull brown as revived in KOH.
Basidia 4-spored, 12-15 x 7-8 [t, hyaline in KOH. Pleurocystidia scattered,
32-40 x 9-14 p, utriform, wall hyaline, smooth and thin, content not distinctive in
KOH (not tested in Melzer's). Cheilocystidia similar to pleurocystidia.
Pileus with a cuticle of vesiculose cells about two cells deep, numerous filamentose hyphae arising from the layer and having an intracellular pigment
brownish-ochraceous as revived in KOH. Clamp connections present.
Type locality. Xuchiles, Mexico.
Habit and habitat. Solitary to gregarious on rotten wood or humus.
Distribution. Mexico.
Observations. This species is most similar to P. weberi, but should differ in
having a white stipe and paler squamules on the pileus (type studied).
17. Psathyrella subtruncatispora A. H. Smith, sp. nov.
Pileus (1-)3-6(-8) cm latus, demum late convexus, spadiceus, fibrillosus, ad
marginem appendiculatus; sapor mitis; lamellae pallide brunneae demum sordide
vinaceo-brunneae, confertae, latae, adnatae; stipes 3-6 cm longus, 3-6 mm crassus,
fibrillosus, deorsum spadiceus; sporae 6.5-7.5 x 4-4.5 x4.5-5,u, ad basem subtruncatae; pleurocystidia 38-52 x 10-14 x 8-11 A, subcapitata; caulocystidia clavata, circa 18 t lata. Typus. Smith 78076 (MICH); legit prope Vanderbilt,
Michigan.