164 CYSTOPTERIS 



COMMON BLADDER FERN: 



Cystopteris frdgilis^ 

 (^Filix fragilis.) 



Fronds acute^ seldom more than 15 inches long, 

 twice or three times pinnate; pinnae mostly acute, 

 pinnate or pinnatifid with narrow, lobed or toothed 

 pinnules; fronds variable in their shape and cut- 

 ting; stipe fully as long as the blade. It is some- 

 times confused with JVoodsia ohtusa, but the pinnae 

 and pinnules of JVoodsia are usually broader and 

 more obtuse, and the indusium opens in a decidedly 

 different manner from that of the bladder ferns. 



Fruit dots rather small and thickly scattered over 

 the lobes of the pinnules; indusium taper-pointed 

 when young, attached to the pinnules by the base, 

 and opening on the side toward the ajoex of the 

 lobes, soon disappearing. 



Found on shaded cliffs and in rocky woods, 

 widely distributed. 



