(Greek, bladder-fern). Polypodid-cese. Native ferns, with delicate foliage; deserve to be planted in the hardy fern garden.

Sori round, covered by a delicate indusium which is attached under one side and opens at the other, becoming hood-like in appearance and finally disappearing. The 5 species are native in the north temperate zone. Of easy cult, in shady, rich borders.

Bulbifera

Bernh. Leaves 8-24 in. long, dark green, 3-5 in. wide, widest at the base, long tapering, tripinnatifid, bearing on the under surface of the rachis a series of bulb-like bodies, which germinate and prop, new plants. Canada to N. C. - Thrives best on lime-bearing rocks. Exceptionally useful and attractive on damp rocky banks.

Fragilis

Bernh. Fig. 1200. Leaves clustered, gray-green, 4-8 in. long besides the slender stalks, tripinnatifid, widest above the base. Widely distributed over the world at all altitudes. l. M. Underwood.

Fig. 1200. Cystopteris fragilis. (X 1/3)