Cystopteris
(from kystis, a bladder, and pteris, a fern). Bladder Fern. ORD. Filices. A genus of elegant and graceful little hardy Ferns, allied to Microlepis and Woodsia. Involucre membranaceous, sub-orbicular, inserted by its broad base under the sorus, which, at the beginning, it covers like a hood. Sori globose, placed on the back of the veins. For general culture, see Ferns.
C. alpina (alpine). sti. 2in. to 4in. long. fronds 4in. to 8in. long, 1in. to 2in. broad, oblong-lanceolate, tripinnatifid; main rachis winged above; largest pinnae deltoid, lanceolate, 1in. to 1 1/2in. long, about 1/2in. broad; pinnules ovate-rhomboidal; segments slightly toothed. sori small, two to twelve to a pinnule. Mountains of Europe (Teesdale, England) and Asia Minor. C. bulbifera (bulb-bearing). sti. 4in. to 6in. long. fronds 6in. to 12in. long, 3in. to 4in. broad at the widest part, ovate-lanceolate, often much elongated upwards, bi-or tripinnatifid; lower pinnules lanceolate, 2in. to 3in. long; segments linear-oblong, very slightly toothed. sori two to twelve to a pinnule. North America, 1638. Large fleshy bulblets are formed in the axils of the upper pinnae, which fall to the ground and become new plants. C. fragilis (fragile).* sti. 2in. to 4in. long. fronds 4in. to 8in. long, 1 1/2in. to 2in. broad, ovate-lanceolate, tripinnatifid; largest pinnae 1in. to 1 1/2in. long, 1/2in. to 3/4in. broad; pinnules oblong-rhomboidal; segments bluntly or sharply toothed. sori two to twelve to a pinnule. Temperate regions of both Northern and Southern hemispheres. This elegant little species is admirably adapted for growing in fern cases; it has numerous more or less distinct varieties, the best of which are described below. Other forms are: decurrens, interrupta, obtusa, and sempervirens.
C. f. angustata (narrow). Whole frond attenuated, and sometimes even depauperated. Rarely exceeding 9in. in height.
C. f. dentata (dentate). fronds bipinnate, bluntly toothed. sori very close to the margin. h. 6in.
C. f. Dickieana (Dickie's). fronds 4in. to 5in. in height, rich dark green; pinnae all bending down somewhat, and overlapping each other; pinnules slightly and bluntly toothed. An elegant form.
C. montana (mountain). sti. slender, erect, 6in. to 9in. long. fronds about 6in. each way, deltoid, quadripinnatifid; lowest pinnules deltoid-lanceolate, 1in. to 1 1/2in. long, about 1/2in. broad; segments cut down to the rachis below; lobes oblong, deeply and sharply toothed. sori small, eighteen to twenty-four to the lower segments. rhiz. wide creeping. Scotland (very rare), Mountains of Northern hemisphere.