636 THE TEKK FAMIIT. 



XIII. ADIANT. ADIANTUM. 



Fronds usually deUcate and divided, the segments more or less wedge- 

 shaped, with diverging forked veins, usually without a midrib. Sori oblong 

 or linear, transverse, at the ends of the lobes on the under side, vrith an in- 

 dusium formed from the edge of the frond and opening outwards. 



A considerable and well-marked genus, chiefly tropical. 



1. Maidenhair Adiant. Adiantum Capillus- Veneris, Linn. 

 (Eng. Bot. t. 1564. Maidenhair.) 



A very delicate tufted Fern. Fronds 6 inches to near a foot long, twice 

 or thrice pinnate, usually broadly ovate in general outhne, their slender 

 stalk of a shining brownish-black. Segments obovate or fan-shaped, 4 to 

 8 lines broad, aU 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 converging 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 south-western counties of Eng- 

 land, in South Wales and Ireland. Fr. all summer. 



XIV. BI.ADDERFERN. CYSTOPTERIS. 



DeUcate Ferns, with twice or thrice pinnate fronds. Sori small, cir- 

 cular 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. 



Prondsoblong-laneeolate, the lowest pinnas decreasing in size . . . 1. Brittle B. 

 Fronds broadly triangular or rhomboidal, the lowest pair of pinnas 



the largest 2. Mountain B. 



1. Brittle Bladderfem. Cystopteris fragilis, Bemh. 

 {Cyathea fragilis and dentata, Eng. Bot. t. 1587 and 1588.) 



Eootstock shortly creeping. Fronds tufted, usually u.nder a foot long, 

 oblong-lanceolate in their general outline, twice pinnate ; the longest primary 

 pinnas towards the middle of the frond, 1 to 1^ inches long, decreasing 

 towards both ends. Stalks slender, without scales. Segments lanceolate, 

 deeply pinnatifid, or the lower ones pinnate, with small, oblong, more or 

 less crenate lobes, all obtuse, not pointed, as in the roch Spleenwort, to the 

 larger specimens of which this plant bears some resemblance. 



On rocks and old walls, spread over the greater part of the globe, espe- 

 cially in mountainous districts, extending far into the Arctic regions. Dis- 

 persed over all Britain, and common in the hOly districts. Fr. summer and 

 autumn. A closely allied species (if reaUy distinct), from the Alps and Py- 

 renees, the C. alpina {Cyatliea ineisa, Eng. Bot. t. 163), is usually included 



