The North American species of Psathyrella.

1972]

PSATHYRELLA

361

content not distinctive in either KOH or Melzer's. Cheilocystidia similar to
pleurocystidia but scattered or very small clavate to vesiculose cells present
(7-10 p wide) in addition. Caulocystidia scattered, clavate to subclavatepedicellate, 45-57x10-18 /, thin-walled, hyaline.
Cuticle of pileus of large vesiculose to vesiculose-pedicellate cells, the layer
1-2 deep, the cell walls yellowish in KOH, smooth. Hyphae of the subcuticular
region dingy cinnamon fading to pallid (revived in KOH), hyphal walls smooth.
Clamps present. No distinctive reactions on any tissue when mounted in Melzer's.
Type locality. Tahquamenon Falls State Park, Luce County, Michigan.
Habit and habitat. Gregarious on hardwood logs, June.
Distribution. Michigan.
Observations. This species is close to P. hydrophila but has even less veil than
the latter, slightly different pleurocystidia and slightly different spores. In southeastern Michigan we have a form which becomes milk-white before moisture has
escaped and the colors accompanying spore maturation have set in. The context,
however, gives a dark vinaceous reaction in KOH as revived. Hoseney 1445 and
1474 represent this variant. Its spores are often almost rectangular in face view.
It may represent a distinct species.
Material examined. Michigan: Hoseney 1445, 1474; Smith 63474 (Type).
334. Psathyrella subcaerulea A. H. Smith, sp. nov.
Pileus 6-12(-15) mm latus, conicus vel convexus, glaber, rufo-fulvus demum
fumoso-fuscus; lamellae confertae, latae, sordide brunneae demum purpureobrunneae, ad acierum demum incarnatae; stipes 1-2.5(-3) cm longus, filiformis,
griseus, ad basem caeruleo-myceliosus; sporae 6-7x 4.2-4.8 11; pleurocystidia
38-47 x 9-13,, fusoideo-ventricosa, rotundata vel obtusa; fibulae adsunt. Typus.
Smith 55549 (MICH); legit prope Grants Pass, Oregon.
var. subcaerulea
Pileus 6-12(-15) mm broad, obtusely conic becoming convex or remaining
unexpanded, surface glabrous, moist and hygrophanous, dark rusty brown moist
but becoming more chocolate-brown as spores mature, fading to dingy avellaneous
but drying dark grayish brown; margin naked. Context thin and fragile.
Lamellae close, broad, adnate, dark brownish, becoming purple-brown from the
spores, edges pallid and crenulate but becoming pink by late maturity.
Stipe 1-2.5 (-3) cm long, less than 1 mm thick (filiform), very fragile, grayish
and naked to or at apex, faintly pruinose above, brownish below to the basal
tomentum which is pallid at first but soon becomes bluish.
Spores 6-7 x 4.2-4.8 I, smooth, pore very minute but apex obscurely truncate,
shape in face view elliptic to ovate or some obscurely angular, in profile obscurely
bean-shaped to obscurely inequilateral or ovate, color in KOH that of a roasted
coffee bean but soon grayer (becoming chocolate-gray), in Melzer's fulvous, wall
about 0.2, thick.
Basidia 4-spored, 12-18 x7-9 /, short-clavate, hyaline in KOH. Brachybasidioles present in age (but basidia may be nearly globose also). Pleurocystidia
38-47 x 9-13 /, fusoid-ventricose with elongated neck and rounded to the obtuse
apex varying to utriform to narrowly ventricose-capitate, wall thin, smooth and
hyaline, content not distinctive. Cheilocystidia similar to pleurocystidia but more
with broadly rounded apex, some with yellow walls in KOH and clavate to fusoid
but if the latter the apex blunt.