The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[VOL. 24

Illust. Text Figs. 141,142,144.
Pileus 2-3 cm broad, conic to obtusely campanulate, at first with the remains
of the slightly developed veil decorating the extreme margin but soon glabrous,
white when fresh but becoming dark brown in age and when dried more or less
avellaneous.
Lamellae broadly adnate, subdistant, narrow to moderately broad, pallid
becoming dark purple-brown, edges whitish.
Stipe 4-6 cm long, 4-6 mm thick at apex, enlarged downward or nearly equal,
surface densely pruinose-pubescent over all, base white fibrillose, white or whitish
throughout but tinged brownish when dried.
Spores 15-18x 10-12 /, smooth, apical pore small but bubble-like, shape in
face view broadly ovate to elliptic (to a somewhat pointed base) as revived in
KOH, as revived in Melzer's somewhat angular-ovate as in Panaeolus spores, in
profile view subelliptic or obscurely inequilateral, dark blackish brown in KOH
but slowly dark chocolate-color on standing (immature spores becoming chocolate
color first), in Melzer's dark bay-brown, wall about 1.5 p. thick.
Basidia 30-45 x 10-15 p, 4-spored, broadly clavate, hyaline in KOH. Pleurocystidia rare and mostly near the edge, 30-52 x 10-20 p, broadly fusoid-ventricose
to subutriform (apex subcapitate), smooth, hyaline, thin-walled, content not
distinctive in KOH or Melzer's. Cheilocystidia similar to pleurocystidia. Caulocystidia numerous and versiform, clavate and 26-35 x 10-15 p. to 80 x25 /, subcylindric and 40-70 x 10-15 /, utriform or ventricose with broadly rounded apex
and 40-50 x 12-18 p, all smooth, hyaline or walls weakly ochraceous, thin-walled,
content not distinctive. Stipe cortex filled with hyaline laticiferous hyphae, also
hyaline in Melzer's.
Pileus with a cuticle formed by an hymeniform layer of hyaline pear-shaped
to subsaccate cells 26-40 x 12-25 p. or occasional cells up to 60 x 30 p. and clavate,
some broadly rounded ventricose pileocystidia also present. No distinctive color
changes evident in mounts made in Melzer's. Clamps present.
Type locality. Plant of Celotex Company, Louisiana.
Habit and habitat. On bagasse piles from sugar mills in wet places.
Distribution. Louisiana.
Observations. The angularity observed on spores in Melzer's disappeared in
about a half hour in the solution. The species is not a Panaeolus as the gills
apparently (from the material examined) are not mottled, the color change of
the spores in KOH is typical of Psathyrella, as is also the fibrillose veil. Its
distinctive features are the large thick-walled spores with the bubble-like germ
pore (as revived in KOH), and the motley assemblage of types of caulocystidia.
56. Psathyrella incrustans A. H. Smith, sp. nov.
Pileus 2-3 cm latus demum planus, glaber, hepaticolor, ad marginem appendiculatus; lamellae latae (5 mm) adnatae vel subdecurrentes, secedentes,
subdistantes dilute brunneae demum subhepaticolor; stipes 2-3 cm longus, 4-6
mm crassus, fibrillosus, intus brunneolus; sporae 9-11x 5-6.5 /; fibulae adsunt.
Typus. Smith 18929 (MICH); legit South Lyon, Michigan.
Illust. Text Figs. 143, 145, 146.
Pileus 2-3 cm broad, obtuse to convex, expanding to plane, surface glabrous
and moist, dark liver-brown when fresh, avellaneous when faded, hygrophanous,
veil fragments fringing the margin at first but soon disappearing. Context
moderately thick and not distinctly fragile, avellaneous when moist, paler when
faded, odor and taste not distinctive.
Lamellae broad (about 5 mm), broadly adnate to subdecurrent, soon seceding,