142 
HISTORY OF BRITISH FERNS. 
will grow freely, provided they are not much exposed to 
the sun, which they do not like. 
Asplenium fontanum, B. Brown. 
The Smooth Bock Spleenwort. (Plate XIII. fig. 2.) 
This is a small tufted-growing species, seldom seen 
more than three or four inches high under ordinary cir¬ 
cumstances ; in a hothouse, where its parts become more 
lengthened, it sometimes reaches eight or ten inches high, 
but this stature is but rarely attained. The small fronds 
are evergreen, and mostly grow nearly upright; they are 
of a narrow, lanceolate form, rather rigid in texture, of a 
deep green above, paler beneath, and supported on a very 
short stipes, which has a few- narrow pointed scales at the 
base. They are bipinnate, the pinnae oblong-ovate, and 
the pinnules obovate, tapering to the base, the superior 
basal pinnule of each pinna having the margin divided by 
four or five deep sharp teeth, the rest of the pinnules and 
lobes having from one to three similar teeth. The main 
rachis of the frond, as well as the partial rachis of each 
pinna, has a narrow winged margin ; that is to say, a very 
narrow leafy expansion along tbeir sides, throughout their 
length; and this is, perhaps, the most obvious technical 
