FERN FAMILY 71 



FRAGILE BLADDER FERN. 



Cystopteris fiagilis. 



Frond bi-tripinnate, the pinnas and pinnules 

 irregularly cut-toothed or pinnatifid and usually 

 decurrent along the winged rachis. The pinnae 

 are rather remote and the pinnules vary con- 

 siderably in their form and cutting. 



This fern grows from six to twelve or fifteen 

 inches high, and is found on moist, shaded cliffs 

 and in rocky woods, common. 



It strongly resembles Blunt-lobed Woodsia 

 but may be distinguished by the less triangular 

 form of its piitncB, by the ^ong, bare stipes, and 

 a certain gracefulness of growth peculiar to it- 

 self. The stipes of young fronds are somewhat 

 hairy-chaffy. 



Other names for it are the Brittle Bladder 

 Fern and Common Bladder Fern. 



Its fronds are among the earliest to appear in 

 the spring. By the middle of summer they fre- 

 quently wither and disappear, and fresh fronds 

 often spring up in August. 



Nearly all of the fronds are fertile. The fruit- 

 dots are numerous, round and large, near the 

 margin of the pinnules, and sometimes, becom- 

 ing quite heavy, give the fronds a somewhat 

 coarse appearance which is wholly lacking be- 

 fore the fruit matures. 



