The sporangia have twenty-six or twenty-eight articulations of the ring. The spores are dark-colored and ovoid.
Imperfectly fertile fronds are often found, which are analogous to the “obtusilobata” condition of O. sensibilis.
ALPINE BEECH-FERN.
FRAGRANT WOOD-FERN.
PHEGOPTERIS ALPESTRIS, Mettenius.
Alpine Beech-Fern.
Phegopteris alpestris:—Root-stock short and thick, erect or oblique; stalks sub-terminal, four to ten inches long, bearing a few brown spreading scales near the base; fronds one to two feet long, oblong-lanceolate, membranaceous, smooth, pinnate with delicately bi-pinnatifid deltoid-lanceolate pinnæ, the lower ones distant, and decreasing moderately; pinnules ovate-oblong or oblong-lanceolate, doubly incised and toothed; sori small, rounded, naked, usually copious on all or all but the lowest pinnæ.
Phegopteris alpestris, Mettenius, Fil. Hort. Lips., p. 83; Phegopteris, p. 10.
Polypodium alpestre, Hoppe, “in Spreng. Syst. Veg., iv., par. ii., p. 320.”—Koch, Syn. Fl. Germ., “ed. 2, p. 974;” ed. 3, p. 731.—Moore, Nat. Pr. Brit. Ferns, t. vii.—Hooker & Arnott, Brit. Fl., ed. 7, p. 582.—Hooker, Brit. Ferns, t. vi.; Sp. Fil., iv., p. 251.—Hooker & Baker, Syn. Fil., p. 311.
Aspidium alpestre, Swartz, Syn. Fil., p. 421.—Schkuhr, Krypt. Gew., p. 58, t. 60.
Asplenium alpestre, Mettenius, Asplenium, p. 198, t. vi., figs. 1-6.