THE BLADDER FERNS. 



HE 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- 

 plied to these species in allusion to the 

 indusium which is hood-shaped and 

 ^attached to the frond by the broad 

 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 FUix. 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 Filix will ever be accepted. 



"The Common Bladder Fern. 



Shaded rocks in almost any locality are likely to har- 

 bour the common bladder fern (Cystopteris 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 



