GENUS V. 
CYSTOPTERIS, BernhardL 
BLADDER FKRX. 
GEN. CHAR. Sori roundish, small, medial, attached at 
the back of the venules. Indusium hooded or cucullate, 
fixed by its broad base beneath the sori (which it covers 
when young), the free margin fringed, and directed to- 
wards the apex of the segment, at length reflected. Veins 
free; mid vein distinct, sinuous; venules simple. 
The Bladder ferns are all very elegant plants, with much 
divided fronds, of delicate texture ; and easily cultivated. 
The name is derived from the Greek kystos, a bladder, 
and pteris, a fern ; in allusion to the peculiar form of the 
indusium. 
1. Cystopteris fragilis, BernhardL Brittle 
Bladder-fern. Fronds lanceolate bipinnate : pinna ovate- 
lanceolate, or oblong-lanceolate ; pinnules ovate, or ovat*- 
lanceolate, pinnatifid or toothed. The following are dis- 
tinguishable, though closely connected forms : 
a. vulgaris: fronds lanceolate ; " pinnules ovate-acute 
pinnatilid, cut, or serrated ;'' sori sub-central, becoming 
confluent. 
