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HISTORY OF BRITISH FERNS. 
ones, but closely resemble those of cristata, the fertile ones 
having much more the appearance of those of the mr. 
spinulosa, only that they are narrower, and have narrow 
pinnae. The outline of these fertile fronds is narrow 
lance-shaped, the pinnae having a narrow tapering form, 
and the pinnules being oblong-pointed, with rather deep, 
serrated, marginal notches, the serratures terminating in a 
fine point. The midvein of the pinnules is tortuous, 
giving off branched lateral veins, the anterior of which 
bears a sorus, so that these latter are placed in two regular 
lines lengthwise on each pinna; the sori are produced from 
the base to the apex of the frond, and are covered by even- 
margined, kidney-shaped scales or indusia. The barren 
fronds are broader, usually shorter, less erect, and their 
pinnules are of a broader, blunter form, and more closely 
placed, than those which are fertile. Sometimes after the 
growth of the first set of fertile fronds others spring up 
which are also fertile, but have the appearance described 
above as peculiar to the barren ones ; these fronds being 
undistinguishable from cultivated fronds of L. cristata. 
This plant is found on boggy heaths, generally in company 
with cristata and spinulosa ; but it is comparatively rare. 
The variety spinulosa, known as the Narrow Prickly- 
