‘Adiantum.] XCIV. FILICES. 569 
stalk of a shining brownish-black. Segments oboyate or fan-shaped, 
4 to 8 lines broad, all narrowed at the base into a short, slender stalk, 
more or less divided into wedge-shaped, obtuse lobes, thin, and of a 
bright green, without any midrib, but numerous forked veins converg- 
ing at the base. Sori conspicuous, occupying the extremities of most 
of the lobes of the segments. 
In the fissures of moist rocks, at the entrance of caves and wells, and 
other situations sheltered from cold, as well as from sun and drought, 
in most of the tropical and warmer parts of the globe, common in 
southern Europe, extending northward over the greater part of France, 
but scarcely into Germany. In Britain, only in the southern and western 
counties of England, in South Wales, the Isle of Man, and Ireland. 
Fr, all summer. 
XIV. CYSTOPTERIS. BLADDERFERN. 
Delicate Ferns, with twice or thrice pinnate fronds. Sori small, 
circular, on the under surface, enclosed, when young, in a very thin, 
globular, or hood-shaped membrane, which opens out irregularly into a 
cup under one side, and often disappears early. 
A small genus limited to the colder or mountainous regions of both 
hemispheres. 
Fronds oblong-lanceolate, the lowest pinnas decreasing in size . iL. C. fragilis. 
Fronds broadly triangular or rhomboidal, the lowest aad of poe 
the largest : ; . 2. C. montana. 
1. C. fragilis, Bernh, (fig 1810), Brittle _B.—Rootstock shortly 
creeping. Fronds tufted, usually under a foot long, oblong-lanceolate 
in their general outline, twice pinnate; the longest primary pinnas 
towards the middle of the frond, 1 to 14 inches long, decreasing 
towards both ends. Stalks slender, without scales. Segments lanceo- 
late, deeply pinnatifid, or the lower ones pinnate, with small, oblong, 
more or less crenate lobes, all obtuse, not pointed as in Asplenium 
fontanum, to the larger specimens of which this plant bears some 
resemblance. 
On rocks and old walls, spread over the greater part of the globe, 
especially in mountainous districts, extending far into the Arctic 
regions. Dispersed over all Britain, and common in the hilly districts. 
Fr. summer and autumn. A variety from the Alps and Pyrenees, C. 
alpina, Desv., with a 3- 4- pinnate frond, is found in Teesdale. [Another 
variety is C. dentata, Sm., with ovate-lanceolate obtuse segments, and 
submarginal sori. | 
2. ©. montana, Bernh. (fig. 1311). Mowntain B.—Rootstock creep- 
ing. Fronds growing singly, twice or thrice pinnate, broadly triangular 
or rhomboidal in general outline, the pinnas of the lowest pair being 
considerably larger and more divided than the others, as in Polypodiwm 
Dryopteris, which this plant much resembles. It is, however, of a more 
delicate texture, only 6 or 8 inches or rarely a foot high, including the 
long slender stalk ; the pinnas are mostly alternate, with more divided, 
smaller segments, ‘and the slender indusium over the sori is easily seen 
under a magnifying-glass when young. 
