The North American species of Psathyrella.

1972]

PSATHYRELLA

71

32a. Psathyrella kauffmanii var. exannulata A. H. Smith, var. nov.
A typo differt: stipes tenuiter fibrillosus, glabrescens; annulus nullus. Typus.
Smith 6285 (MICH); legit prope Highland, Oakland Co., Michigan.
Illust. Pls. 18, 94; Text Fig. 101.
Pileus 3-8 cm broad, oval to obtusely conic becoming nearly plane, surface
moist and hygrophanous, glabrous or with zones or patches of veil fibrils along the
margin, margin at first appendiculate from patches of the submembranous partial
veil, color when moist "Prout's brown" to "cinnamon-brown" to "snuff brown" or
"buckthorn brown," fading finally to "warm buff" to "pinkish buff" (pale dingy
ochraceous to pale tan), surface radially rugulose at times, margin often striatulate when moist. Context watery brown, fading to pallid, fragile, thin, odor and
taste not distinctive.
Lamellae close to crowded, narrow to moderately broad, bluntly adnate,
seceding, pallid grayish and finally fuscous brown to purplish brown, edges
even.
Stipe 7-12 cm long, 4-8 mm thick equal or narrowed to a pointed laterally
rooting base, fragile to firm, hollow, surface thinly appressed fibrillose over
lower portion, glabrescent, apical region faintly pruinose-striate, white over all
and unchanging or merely slightly discolored generally in age.
Spore deposit dark purple-brown (with a slight red component). Spores
7-8.5 (-9) x 4-4.5 a, smooth, apex somewhat truncate from a distinct pore, shape
in face view narrowly ovate to elliptic with the base of many of them somewhat
truncated (spore tending to be wedge-shaped to a slight extent), in profile
somewhat bean-shaped to obscurely or somewhat inequilateral (apical region in
some drawn out slightly, color in KOH cocoa-color and remaining so a long
time in KOH, finally darkening slightly), in Melzer's tawny reddish, wall about
0.2 I thick.
Basidia 4-spored, 18-23 x 7-9 f, clavate, hyaline in KOH. Brachybasidioles
not differentiated from basidioles. Pleurocystidia 35-45(-50) x 10-18 [4, utriform
to broadly fusoid-ventricose with broadly rounded to capitate apex, wall thin,
smooth, hyaline and not highly refractive, content not distinctive in KOH or in
Melzer's. Cheilocystidia 20-35 x 10-20 a, broadly clavate, saccate, or vesiculose,
thin-walled and hyaline. Caulocystidia more or less like the pleurocystidia but
fewer of them utriform.
Pileus with a cuticle of vesiculose cells 1-2 deep, the cells with thin, hyaline
to slightly ochraceous walls and content of cell not distinctive. Hyphae of the
trama in the subcuticular region vinaceous-brown in young basidiocarps when
first revived in KOH, fading, hyphal walls smooth, some intercellular hyaline
debris in the layer. When mounted in Melzer's no distinctive color changes
were evident. Clamps present.
Type locality. Haven Hill, Highland Recreation Area, Oakland County,
Michigan.
Habit and habitat. Subcespitose-gregarious under beech, June and October.
Distribution. Alabama, Illinois, Michigan, Oregon, Tennessee.
Observations. This is a genetically constant entity fruiting at the same time
as the type variety and never observed with a persistent annulus. However,
it is so similar to the type variety in all other respects that it seems unjustifiable
to recognize it as an autonomous species. It may possibly differ in shorter more
capitate pleurocystidia, but here there is much intergradation. Psathyra fatua
sensu Lange, with spores under 5,u wide, may be this variant.