The Botany of Iceland - 01.12.1932, Blaðsíða 98

546
POUL LARSEN
at flrst coloured like the cap, then more tawny, edge dentate. — Basidia
clavate, 4-spored. — Spores tawny, spherical or broadly ellipsoidal,
echinulate, the smallest 5X5 p, the mediumsized 6.5X5—6 p. and the
largest 7.5X5.5—6 fi. — No cystidia.
Allied to C. nidulans (Pers.) Quélet, yet easy to distinguish both
macro- and microscopically.
Psalliota Fries.
563. P. campestris (Linné) sensu J. E. Lange, Dansk Botanisk Arkiv,
vol. 4, No. 12, p. 9.
Vallanes in Lagerfljót [P. L.]. — In manured homefields.
Cap at flrst hemispherical with incurved margin, then expanded,
convex with straight margin, flesh thick, reddening faintly when broken,
surface silky and white. — Stipe subcylindrical, stuífed, surface like tliat
of the cap, bearing an evanescent ring splitting up into hairs. — Gills
free, at flrst pale, then red, at length dark brown. — Spores somewhat
irregularly ovoid, smooth, purple brown, 6.5—8X4.5—5 p.
Note. Several other localities have been recorded by collectors,
though it has not been possible to ascertain what they meant by P.
campestris, viz. Grimsey [O. D.], lieaths by Grjótnes and Akureyri [C. H. O.],
Möðruvellir [St. St.], Vallanes [Helgi Jónsson].
564. P. Elvensis Berkeley et Broome var. alba n. var.
By Laxá south-west of Mvvatn [P. L.]. — On mounds of earth round
sheepfolds.
Pileus 7—14cm broad, campanulate with incurved margin, white
or dingy white, cuticle thick, splitting up into patches ending with de-
ilexed and upward curving points, flesh thick, white, reddening faintly
when bruised, witli a yellow tinge below the cuticle. — Stipe subcylin-
drical but with the hase attenuated, fistulose, fllled below with a felty
pith; ílesh of stipe like that of cap, but citron-yellow in the lower part.
Ring raised, skin-like, single. — Gills at íirst pale, then incarnate (m 3),
íinally dark reddish brown (c 3), up to 12 mm broad, crowded, rounded
towards the stipe, free. — Basidia 4-spored. — Spores spherical or broadly
ellipsoidal, the spherical spores are 6 p, in diameter, the ellipsoidal ones
7—7.5Xö//. Differing especially in the colour of thc pileus.
565. P. arvensis (Schaell'er) sensu Ricken.
Agaricus arvensis Schaeffer, Fung. Ic., t. 310 and 311.
Rej'kjahlíð near Mývatn [P. L.].— Under scattered birches on Iava íields.
Pileus 7— lOcm broad, convex, then plano-convex, silkyhaired or
squamulose, white to whitish yellow; Ilesh white, assumes a yellow tinge
when bruised. — Stipe cylindrical, bulbous, hollow, white, at length
hecoming sooty, bearing a double ring, the lower layer radiately rimose.
— Gills at flrst almost white, hecoming greyish red and linally almost
hlack, broadest in front, free. Basidia 4-spored. — Spores ellipsoidal,
smooth, purple hrown, 7—7.5X 4—4.5 p.