The North American species of Psathyrella.

150B

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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Pileus with a cuticle of vesiculose cells-mostly about 2 cells deep but the
cells not greatly enlarged (10-30) A, walls smooth, hyaline and thin, content of
cells not distinctive in KOH or Melzer's. Hyphae of the trama in the subcuticular
region weakly ochraceous in KOH, the walls smooth. Clamp connections present.
No distinctive reactions on any tissue in mounts made in Melzer's.
Type locality. University of Michigan Biological Station, Cheboygan, Michigan.
Habit and habitat. Scattered on mossy logs, stumps or dead trees of Fraxinus
(ash), June.
Distribution. Michigan.
Observations. The long cystidia frequently are the narrowest. This species
features a pallid pileus at first, pallid gills which become dark grayish brown,
and spores tending to be slightly compressed. The globule in the pleurocystidia
shows in some as a pale yellow mass in Melzer's. For a comparison with P.
madeodisca see that species. The relationships of P. fraxinophila appear to be
with that species, but P. madeodisca is readily distinct by its darker color when
young.
Material examined. Michigan: Smith 25207, 25299 (Type), 25305, 25334,
25335, 25336, 25387, 25591, 25593, 25596, 25600, 25781, 26013, 26020, 28742,
28744,32302,36395,36517,36586,71550,71706.
105. Psathyrella tsugae A. H. Smith, sp. nov.
Pileus 4-8(-10) cm latus, obtuse umbonatus, glaber rugulosus, ad marginem
appendiculatus, fusco-cinnamomeus; lamellae confertae, latae, cinnamomeae
demum fumoso-cinnamomeae; stipes 5-10 cm longus, 1-1.5 cm crassus, pallidus,
demum brunneus; sparse fibrillosus, glabrescens; sporae 7-9x3.7-4.5 t; pleurocystidia 34-48 (-60) x 9-13 /, lecythiformia; fibulae adsunt. Typus. Smith 77849
(MICH); legit prope Hulbert, Michigan.
Illust. Text Figs. 261-263.
Pileus 4-8 (-10) cm broad, obtusely umbonate with a spreading margin,
expanding to broadly convex or nearly plane, glabrous, radially rugulose, appendiculate on the margin, color dark rusty brown when moist ("Mars brown"),
subhygrophanous and near cinnamon-brown when moisture has escaped, when
dried dark rusty brown. Context firm to very firm, colored more or less like
the pileus surface, odor and taste not distinctive.
Lamellae adnate, close, moderately broad, of equal width near to the pileus
margin, dark rusty brown in youngest specimen seen, nearly the same color when
mature, slightly darker as dried, edges even.
Stipe 5-10 cm long, 1-1.5 cm thick, equal or enlarged somewhat near apex,
pallid at first, brownish when mature, surface glabrous or thinly coated with
veil fibrils at first but soon glabrescent, apex faintly pruinose.
Spores 7-9 x 3.7-4.5 u, smooth, apical pore present but apex rounded, in face
view oblong to truncate-ovate (the base truncated), a few more or less wedgeshaped, in profile more or less bean-shaped, color in KOH dark rusty brown
to dark cocoa-brown, slowly becoming more dark chocolate-color, in Melzer's
bay-brown (not as red as in most species), wall about 0.2 A thick.
Basidia 4-spored, 20-24x 6-7 p, narrowly clavate, hyaline in KOH. Pleurocystidia abundant, 34-48 (-60) x 9-13 I, mostly short nine-pin-shaped, walls
smooth, thin and hyaline to yellowish in KOH. Cheilocystidia similar to short
pleurocystidia (ventricose-capitate and with hardly any neck), walls often