THE BRITTLE BLADDER FERN. 
Cystopteris fragilis.* — Bernhardt. 
The Bladder Ferns ( Jcystos is Greek for bladder) are 
so called because the indnsium, even in age inflated or 
bulged out like a hood, has when young the look of a 
flask or bladder. The plant differs in this from the 
flatness (the sori in both being round) of the Poly- 
stichums and Lastreas with which it was formerly 
ranked, under the general name of Aspidice. There 
are three British species of Bladder Ferns : the Brittle 
or Fragile — Cystopteris fragilis , the Alpine — C. regia , 
and the Mountain — C. Montana ; but only the first 
is really authenticated as belonging to the Lake 
Country, no claim being made for C. Montana , and 
the likelihood of C. regia depending only on the 
following paragraph in Moore’s last edition: — “We 
have not seen a native mountain specimen of C. regia 
unless it be one from Saddleback (Blencathra), in 
Cumberland, gathered many years since by Mr. S. F. 
Gray.” There appears indeed to be only one authen- 
ticated habitat of the plant in England : that at Low 
Leyton, in Essex. 
* Polypodimn fragile ( Linnceus ), Aspidimn fragile, Athyrium 
fragile, Asplenium fragillinram. 
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