The North American species of Psathyrella.

228

MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

cinnamon as revived in KOH (finally nearly hyaline), wall smooth and thin, cell
content not distinctive; some cells in the layer projecting as broadly fusoid to
fusoid-ventricose pileocystidia. Hyphae of the subcuticular region pale dingy
vinaceous-cinnamon revived in KOH and with smooth walls. Clamp connections
present. No distinctive reaction seen on any tissue when mounted in Melzer's.
Type locality. Ann Arbor, Michigan.
Habit and habitat. Scattered to subcespitose on sticks of elm and red maple
and on chip-dirt of hardwood trees, etc.
Distribution. Michigan.
Observations. There is no red tinge to the gills. The small spores, branched
pleurocystidia, and dingy yellow-brown color beneath the veil are distinctive.
Material examined. Michigan: Smith 21384 (Type), 32058, 34085, 34086,
34201, 36251, 10-24-48, 11-24-48.
185. Psathyrella subcaespitosa A. H. Smith, sp. nov.
Pileus 1.5-3 cm latus, obtuse conicus demum late convexus, albo-fibrillosus
glabrescens, ad marginem appendiculatus, spadiceus vel fumoso-cinnamomeus;
lamellae pallidae demum avellaneae dein brunneo-griseae, latae, confertae vel
subdistantes; stipes 3-5 cm longus, 2.5-4 mm crassus, fibrillosus glabrescens,
deorsum sordide melleus; sporae 6.5-8 x 4-5 pu; pleurocystidia 36-47 x8-14 I,
fusoide ventricosa vel subcylindrica obtusa; fibulae adsunt. Typus. Smith 27594
(MICH), legit prope Bear Springs, Mt. Hood National Forest, Oregon.
Illust. Text Figs. 422-424.
Pileus 1.5-3 cm broad, obtuse to convex, expanding to broadly conic or convex,
surface at first with a hoary coating of whitish fibrils which soon become arranged
into minute squamules and finally disappear, margin at first appendiculate with
remains of a rather thick cottony-fibrillose partial veil, glabrescent, surface moist
and cinnamon-brown to snuff brown, hygrophanous and fading to grayish buff
and becoming distinctly atomate, margin when moist scarcely translucent-striate.
Context very thin and exceedingly fragile, odor and taste not distinctive.
Lamellae whitish young but soon avellaneous to wood brown and finally nearly
drab but when dried dingy ochraceous-tawny, ascending-adnate and readily
seceding, moderately close and broad, the edges even.
Stipe 3-5 cm long, 2.5-4 mm thick, equal, hollow, fragile, surface densely
fibrillose from pallid veil remnants loosely dispersed to more or less appressed,
glabrescent, pallid beneath the fibrils or in old basidiocarps pale honey-color near
the base, near the apex fibrillose-pruinose.
Spores 6.5-8 x 4-5 /u, smooth, apical pore distinct and some spores with a
truncated apex in optical section, shape in face view ovate to elliptic, in profile
somewhat inequilateral to subelliptic, color in KOH bright ochraceous-tawny
becoming slowly snuff brown and finally clouded with gray, in Melzer's ochraceoustawny to clay color and only slightly reddish on standing, wall about 0.2 p, thick.
Basidia 4-spored, very short and fat (15-18x8-10 A), with scarcely any
pedicel, hyaline in KOH. Brachybasidioles and basidioles practically indistinguishable. Pleurocystidia scattered, 36-47 x 8-14 a, fusoid-ventricose to narrowly
fusoid-ventricose or subcylindric, apex obtuse, wall thin, smooth and hyaline, the
tip area long remaining collapsed (in KOH) but no thickening or refractive nature
observed in the remainder of the wall, content of cell not distinctive. Cheilocystidia 28-42 x 9-15 u, fusoid-ventricose with short neck and obtuse apex vary