The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

Spore deposit dark purple-brown. Spores 8-10 x 4.5-6.5 u, smooth, apical pore
present but apex not obviously truncate, shape in face view corn-kernel-shaped
to obscurely truncate, in profile view obscurely bean-shaped to obscurely inequilateral, color in KOH dull cocoa-brown as revived, dark sooty brown when fresh,
in Melzer's tawny, wall about 0.5 pu thick.
Basidia 4-spored, 15-20 x 6-9 a, short-clavate. Pleurocystidia abundant,
40-50x 13-20 / in ventricose part and 9-12 u near apex, fusoid-ventricose with
broadly rounded apex, hyaline in KOH, in Melzer's some having a small hyaline
to yellowish globule, smooth in either KOH or Melzer's. Cheilocystidia 22-30 X
15-25 i, clavate to saccate, smooth, thin-walled.
Pileus with the outer veil fibrils olive to olive-brown in KOH from dissolved
pigment, cuticle of inflated cells 3-4 deep, walls thin, smooth and hyaline, content
hyaline in KOH. Hyphae of subcuticular region hyaline in KOH, the walls
smooth. Clamp connections present.
Type locality. Alaska.
Habit and habitat. Gregarious to subcespitose on cottonwood logs, July to
August.
Distribution. Areas where cottonwood grows in southern Alaska.
Observations. This species is distinct from P. lepidotoides in the cocoa-colored
spores in KOH which measure up to 6.5 u wide and which change color only
slightly on standing in KOH. From P. hirtosquamulosa it differs in having colored
epicuticular hyphae as revived in KOH. P. subamara has distinctly narrower
spores. It is, apparently, close to Stropharia aculeata Quel. but lacks an annulus.
14. Psathyrella propinqua A. H. Smith, sp. nov.
Pileus 4-8 cm latus, demum plano-umbonatus, pallide spadiceus vel spadiceus,
fibrillosus; sapor indistinctus; lamellae pallidae demum violaceo-fuscae, confertae,
adnatae latae; stipes 7-10 cm longus, 9-14 mm crassus, fibrillosus, deorsum
squamulosus; sporae 7-9x4.5-5.5 x 4-4.5 A, ad basem truncatae; pleurocystidia
34-56 x12-18 A, clavata vel fusoide ventricosa, ad apicerum late rotundata;
caulocystidia sparsa; hyphae epicuticularum intus sordide ochraceae; fibulae
adsunt. Typus. Smith 67000 (MICH); legit Wildwood, Michigan.
Illust. P1. 8, fig. b; P1. 9, fig. a; Text Figs. 29-30.
Pileus 3-8 cm broad, obtuse when young, expanding to plano-umbonate, surface
rather coarsely appressed-fibrillose to fibrillose-scaly from dingy yellow-brown
fibrils or patches of them, over the disc the fibrils dark yellow-brown (near
"bister"), ground color whitish before becoming dusted from the spores. Context
thin, white, taste slightly unpleasant but not lasting, odor not distinctive, with
FeSO4 no reaction.
Lamellae pallid to brownish pallid becoming dark "benzo brown" when mature,
moderately broad, adnate, close, edges even.
Stipe (3-)5-10 cm long, 4-10(-14) mm thick, firm and fibrous, white, surface
squamulose, sometimes lacerate with white to brownish fibrils, cottony-fibrillose
at apex, not discoloring below.
Spore deposit near "benzo brown" (dark violaceous-brown). Spores 7-9 x 4.5 -5.5 x 4-4.5 a, smooth, apical pore present but apex not truncate, wall about 0.4 /
thick, shape in face view ovate to wedge-shaped (angular at base as seen in optical
section and basal line nearly straight), in profile bean-shaped or with a slight
dorsal hump near the apiculus, color in Melzer's reddish tawny, in KOH pale
fuscous to dark-chocolate brown.