The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

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345. Psathyrella columbiana Harrison & A. H. Smith, sp. nov.
Pileus 1-2 cm latus, late convexus, glaber, cinnamomeus demum griseocinnamomeus; lamellae pallidae demum fulvo-cinnamomeae, confertae, subdistantes; stipes 2-4 cm longus, 1.5-2.5 mm crassus, subcaespitosus, subvolvatus,
albidus; velum copiosum; sporae 7.5-10 x 3.5-4.5 /; pleurocystidia 32-47 (-55) x
8-12 p, lanceolata vel anguste fusoideo-ventricosa; subacuta; fibulae adsunt.
Typus. Harrison 6222 (MICH); legit prope Glacier National Park, Canada.
Illust. P1. 58, fig. d.
Pileus 1-2 cm broad, obtuse to convex, rarely obscurely umbonate when
expanded, glabrous, moist, hygrophanous, dark cinnamon young, paler when
mature and margin thin, toned gray. Context thin and fragile.
Lamellae pallid becoming dark russet, or smoky fuscous finally from the
spores, medium broad, close to subdistant, adnate, margin whitish.
Stipe 2-4 cm long, 1.5-2.5 mm thick, equal when mature, arising in clusters
from a coarse pallid rhizomorph, lower fourth with pallid (yellowish pallid as
dried) veil remnants forming a fibrillose volva, white and thinly fibrillose above
the volva nearly to apex but often dusted with the spores.
Spore deposit fuscous; spores 7.5-10 x 3.5-4.5 ), smooth, with a hyaline spotlike apical pore, shape in face view ovate, in profile somewhat inequilateral, color
in KOH almost black (blackish brown), in Melzer's chestnut-brown, wall about
0.2 /i thick.
Basidia 26-32x7-9 v, 4-spored, hyaline, clavate. Pleurocystidia scattered,
32-47(-55) x8-12 u, lanceolate, apex subacute, varying to narrowly fusoidventricose, thin-walled, hyaline in KOH and weakly yellowish in Melzer's.
Cheilocystidia similar to pleurocystidia.
Gill trama with the subhymenium in the form of a broad cellular band
2-4 cells deep, some cells up to 16 x wide, all thin-walled and hyaline; central
strand of the trama poorly defined toward the gill edge, more distinct near the
pileus context, composed of hyaline to brownish elongated and inflated cells
subparallel to interwoven.
Pileus cuticle a palisade of clavate hyaline cells in a hymeniform layer but
this more or less disarranged in age by inflated cells developing between the
original elements of the palisade. Hyphae of the veil filamentose, 3-7 p wide,
thin-walled, clamp connections present at the septa, end cells cystidioid to clavate
and with somewhat thickened walls at the apex, smooth.
Type locality. Glacier National Park, Canada.
Habit and habitat. On leaf mold, cespitose.
Distribution. Known only from the type locality.
Observations. The cespitose habit and distinct fibrillose volva make this a
most unusual species, and one readily identified in the field. The conspicuously
cellular subhymenium is also distinctive.
346. Psathyrella fragrans A. H. Smith, sp. nov.
Pileus 10-25 (-30) mm latus, conicus demum planus, rufo-fulvus, demum
rugulosus; odor fragrans; lamellae brunneolae demum rufo-fulvae, confertae,
latae; stipes 3-5 cm latus, 1-2.5 mm crassus, ad basem luteo-myceliosus, sursum
sparse pruinosus; velum sparsum; sporae 5-6x2-3.5 u; pleurocystidia 28-45x
9-12x6-9 fu, sublecythiformia; fibulae adsunt. Typus. Smith 47114 (MICH);
legit prope Upper Payette Lake, Idaho.