The North American species of Psathyrella.

1972]

PSATHYRELLA

129

fibrillose, apical region pruinose, becoming dingy tan near the base and tinged
vinaceous toward the apex, veil fibrils also discoloring.
Spores 7-9x4-5 a, smooth, with an apical hyaline pore, shape in face view
oblong to narrowly elliptic, in profile obscurely bean-shaped to obscurely inequilateral, color in KOH dark dull cocoa-color slowly darkening, fuscous when fresh
spores are mounted in KOH, pale tawny in Melzer's, wall about 0.3 /u thick.
Basidia 4-spored, 14-20x6-8 g, clavate, hyaline in KOH. Pleurocystidia
abundant, 38-58 x 10-14 a, narrowly ventricose with obtuse to rounded apex or
more broadly fusoid-ventricose and apex broader, wall thin, smooth and hyaline,
content not distinctive in either KOH or Melzer's. Cheilocystidia mostly saccate,
26-36 x 10-18 a, hyaline, thin-walled. Caulocystidia rare to scattered and more
or less like the cheilocystidia.
Pileus with a cuticle of vesiculose cells 2-3 deep, the walls hyaline in KOH
except where the layer adjoins the subcutis, in this region dark cinnamon wall
thickenings occur especially at the angles of the cells, in Melzer's these thickenings
merely ochraceous, the cell content not distinctive. Hyphae of the trama
vinaceous-brown to cinnamon revived in KOH, some wall-thickenings evident
but lacking readily discernible incrustations. Clamp connections present. No
distinctive color reactions noted for any tissue mounted in Melzer's.
Type locality. Near Kalaloch, Olympic Peninsula, Washington.
Habit and habitat. Cespitose, gregarious or scattered on rotting wood of
frondose trees.
Distribution. United States: Colorado, Michigan, Washington; Canada:
Ontario.
Observations. Smith (1941) identified specimens from decaying wood of
frondose trees as P. chondroderma. Continued collecting over the last thirty years
has shown that the American taxon is constant as to habitat, in the brownish
discoloration of the veil and stipe, and in spores consistently 7-9x4-5 g.
Psathyrella chondroderma was originally described as being associated with
pines, and was terrestrial. This is evident on the type at Kew and Cooke's plate
(606) certainly indicates this also. He also pictures the veil remnants as white.
In view of this, and the pattern of species evolution encountered here in North
America relative to these features, I now regard my previous identification as an
error. The American species is characteristically vernal and quite accurately
identified in the field by the discolorations on the veil hyphae either on the stipe
or the margin of the pileus.
Material examined. UNITED STATES. Colorado: Smith 52653, 52879.
Michigan: Smith 25415, 25461, 33445, 37169, 57214, 57714, 57715, 57716, 63477,
66859, 67016, 71691; N. J. Smith 1761. New Hampshire: Miller 543. Oregon:
Smith 20159, 24157, 24456, 24495, 28285. Washington: Imshaug 798, 979; Smith
13240 (Type), 13257, 13604, 13704, 13834, 14142, 14205, 14608, 28874, 28876,
28929, 29522, 29918, 29919, 29185, 29316, 29334, 29655, 29858, 29925, 30169,
30172, 30289, 31174, 31464, 47533. CANADA. Ontario: Smith 4434.
84. Psathyrella ferrugipes A. H. Smith, sp. nov.
Pileus 2.5-5 cm subplanus ad marginem denticulatus castaneus; lamellae
angustae, fulvo-brunneae; stipes 4-11 cm longus, 2.5-7 mm crassus deorsum
demum ferrugineo-fulvus; sporae 7-10 x4-5 j; pleurocystidia 36-48x10-16 /x,
fusoide ventricosa ad apicerum late rotundata, vel pedicellato-elliptica; fibulae
adsunt. Typus. Walters 6-8-40 (MICH); legit prope Cleveland, Ohio.