THE BLADDER FERNS. 
H WE bladder fern family comprises 
less than half a dozen species 
distributed nearly throughout the 
world though most abundant in 
the North Temperate Zone. The 
generic name, Cystopteris, is the 
Greek for bladder fern and is ap- 
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A 45 
base on the inferior side of the sorus 
and arching over it. The species are 
mostly inhabitants of rocks and are usu- 
ally plentiful in mountainous regions. 
Recently the attempt has been made to change the 
generic name to Fid/iv. This name without doubt was 
used for the genus before Cystopteris was, but the latter 
has been universally used by botanists for so long that 
it is very unlikely that /72/7x will ever be accepted. 
The Common Bladder Fern. 
Shaded rocks in almost any locality are likely to har- 
bour the common bladder fern (Cystopterts fragilis). It 
is fond of a niche in the cliff where its fronds may droop 
gracefully outward but also grows on the talus of broken 
rock at their bases and is often found in moist woods. 
In the extent of its distribution, it yields only to the 
