174 
HISTORY OF BRITISH FERNS. 
dusia, whilst the lobes of the barren fronds are serrated ; their 
texture is thin and membranaceous, their surface smooth, 
their colour a cheerful green. The stipes, which is about 
half as long as the frond, and furnished with a few small 
scales at the base, is black and shining, as also are the 
rachides, the ultimate ramifications of which are small and 
hair-like. 
The veins throughout the pinnules are forked on a di- 
chotomous or two-branched plan, from the base upwards, 
the venules lying nearly parallel and extending in straight 
lines towards the margins, those of the barren fronds ter- 
minating in the serratures of tlie margin, but those of the 
fertile fronds extending into the indusium, there forming 
the receptacles to which the spore-cases are attached. The 
sori are oblong, covered by indusia of the same form, each 
consisting of the apex of one of the lobes of the frond, 
changed to a membranous texture, and folded under. The 
sori are, as already mentioned, seated on this membranous 
reflexed lobe, and by this circumstance the genus may at 
once be detected by those who are not conversant with its 
easily recognized primd-facie appearances. 
The Maidenhair is a local plant, though it has a wide 
geographical range. It is found here and there in the 
