CHAPTER III. 
THE BLADDER FERNS. 
I. THE BRITTLE BLADDER FERN. 
Cystopteris fragilis. 
HE name Riven to the delicate and beautiful 
ferns included under the genus Cystopteris , 
is on account of the bladder-like coverings of the 
spores on the backs of their fronds. The fragile 
Bladder Fern is ordinarily seen about six inches 
in height ; but it sometimes grows to the height 
of a foot or more. The frond-stem is tender, 
herbaceous, and very brittle, having just a few 
light-coloured scales at its base. The fronds grow 
from a tufted root-stock, and come up in clusters : 
the crown of the root-stock spreading to admit of 
this. The shape of the frond is lance- like, tapering 
