CYSTOPTERIS. 
153 
liant green, which contrasts well with the lurid tint of 
the stem. This fern is found pretty frequently in the 
Yorkshire dales and also in Wales and Scotland. Mr. 
Johnson states that it was first discovered in Rhsetia, 
and was hence called Polypodium Rhceticum. 
All these varieties are very desirable for the fernery, 
suiting well with the artificial rock work, and flourishing 
luxuriantly wherever the drainage is thorough and a 
good allowance of broken sandstone and sandy loam is 
mixed in its compost. The common form of C. fragilis 
js the freest grower when under cultivation, but the 
more tapering fronds of angustata form a very graceful 
cluster, and the verdure of Dickieana may compete with 
that of a plant of uncurled parsley. 
The Cy st opt er is fragilis is found in numerous localities 
in Europe, Northern Asia, the two Americas, South 
Africa, and New Zealand. 
24. Cystopteris alpina, Desv. Alpine Bladder-fern. 
Caudex creeping or ascending, scaly. Stem tufted, slender, 
brittle. Fronds oblong, lanceolate, tripinnate. Stems of pinnse 
winged. Sori copious, small. 
This fern is of a smaller size than the last described ; 
its pinnules are more distinctly separated, and its leaf- 
lets smaller and more finely cut. It is a dainty little 
plant of exquisite form and delicate hue. 
Several localities have been cited as homes of this 
plant, but, on careful examination, Sir W. Hooker pro- 
nounces the Scotch specimens to be delicate varieties of 
C. fragilis ; the only true specimens of C. alpina grew on 
a wall in the flat part of Essex, and must surely have 
been planted there. 
