550 POUL LARSEN 
The face of the gills bears true cystidia, these are fusiform, 50—10 u, 
with yellow granular contents. 
Psathyra Fries. 
578. P. spadiceo-grisea (Schaeffer) Fries, Hym. Eur., p. 306. 
Lagarfljöt, Reykjahlid and Norötünga [P. L.]. — In copses of Betula 
pubescens and Betula nana. 
Pileus 3—4 cm broad, convex, + gibbous, with striate-sulcate margin, 
flesh thin and brittle, hygrophanous, reddish-hrown when moist (j 3), 
fuscous when dry (k 4). — Stipe shiny white, rigid, flexuose, fragile, 
hollow, distantly and slightly floccose above. — Gills narrow, crowded, 
broadly adnate, pale greyish-brown, then black with white frayed edge. 
— Spores dark-brown, 8—9X5 u, sometimes faintly curved. — Cystidia 
short, cylindrical, swollen in the middle, 30—40X10 u. 
579. P. gossypina (Bulliard) Fries, Syst. Mye. I, p. 310. 
Agaricus gossypinus Bulliard, 1. c., t. 425. f. 2. 
Hallormstadir [P.L.]. — On the ground among twigs and branches 
in birch copses. 
Pileus 2—4 cm broad, convex, gibbous with pellucidly striate margin, 
brown (h 2) when moist, grey (h 4) when dry, the remains of the white 
veil hanging from the margin. — Stipe cylindrical, shining, white, covered 
with a white frayed coating, hollow, brittle. — Gills ventricose, broadly 
adnate, crowded, at first grey then dark-brown. — Spores brown, ellip- 
soidal, 8—9X4—4.5 u. — Cystidia fusiform, drawn out above into a 
short point. 
580. P. bifrons (Berkeley) Fries, Monographia Hym. II, p. 347. 
Agaricus bifrons Berkeley, English Flora V, p. 114. 
Hallormstadir [P. L.]. — Under willows in bogs. 
Pileus up to 3 cm broad, obtusely conico-campanulate, flesh thin or 
skin-like, rugose and pitted at the margin, which is at first covered by 
a thin fugaceous veil, hygrophanous, reddish-brown (j 3) when moist, 
alutaceous (k 1 to j 1) when dry. — Stipe cylindrical-conical, rigid, brittle. 
hollow, white, mealy and floccose above, covered with projecting hairs at 
base. — Gills ascending, adnate, pale grey, then dark-brown, but white 
at the edge. — Spores ellipsoidal, smooth, dark-brown, 13X7 u. — Cy- 
stidia elongate-conical with obtuse apex, 40—50 u long. 
Psathyrella Fries. 
581. P. prona Fries, Hym. Eur., p. 315. 
Agaricus pronus Berkeley et Broome, No. 924. 
Reykjavik [P. L.]. — Roadside by Ellidaa. 
Pileus 1—1.5 cm broad, hemispherical, flesh thin, margin striate, 
sericeo-pulverulent, brown (h3) when moist, livid (e2) when dry. — 
