548 Filices—Cystopterts. 
7. CYSTOPTERIS. 
Rhizome tufted or creeping. Fronds tufted or scattered, 
1- to 4-pinnate, delicate in texture; veins pinnate or forked, 
ultimate venules free. Sori dorsal, globose on the free venules. 
Indusium membranous, convex, attached to the venule below 
the sorus. There are five species from temperate regions. 
The name is from «voris, a bladder, and mrepés, a fern, referring 
to the form of the indusium or involuere. 
1. C. fragilis. Common Bladder Fern.-—A handsome tufted 
Fern from 6 to 12 inches high, with bright green pinnate or 
bipinnate fronds on short brittle stipes. Pinnules triangular 
or ovate; rachis slightly winged. Sori few or many on each 
pinnule. Throughout Britain, though rare in the south, aud 
widely spread in both the north and south temperate regicns. 
C. dentata aud C. Dickiedma are varieties of this species. 
C. montina is a delicate mountain species with 3- or 4- 
pinnate fronds, found at a great elevation in Scotland. 
Ondclea sensibilis is a hardy North American Fern with 
separate barren and fertile fronds. The former are about 18 
inches high, simply pinnate, with long lanceolate toothed pinne, 
and the shorter fertile ones are bipinnate. Indusium inferior, 
bursting irregularly. 
Struthidpteris Germdieu is an allied Fern having the fronds 
disposed in a tufted rosette. The barren fronds are from 2 to 
3 feet high, lancevlate, bipinnate with narrow pinnules. The 
fertile fronds are pinnate, and appear within the barren ones, 
and are much shortcr. A widely diffused plant. Both this and 
the last are very handsome and desirable for planting in damp 
places, on the margins of pools, or partially in water. 
8 WOODSIA. 
Tufted dwarf Ferns with pinnate fronds, of which the stipes 
are usually jointed above the base. Sori globose; indusium 
attached under the sorus, at first cup-shaped and entire, ulti- 
mately breaking up into filiform scyments. There are 14 
species described, from aretic and alpine regions. This genus 
ix dedicated to Joseph Woods, an English botanist, author of 
the ¢Tonrist’s Flora, Ke. 
We hyperborea and W. ileéisis are found in Britain at con- 
siderable elevations in Wales, North England and Scotland. 
In the first the ultimate lobes of the linear-lanceolate fronds 
are entire, and in the second they are crenate, and the frond 
is oadly lanceolate in outline, 
