122 HISTORY OF BRITISH FERNS. 



form as the fertile ones. The barren fronds closely resemble 

 those of cristata, while the fertile ones have much the ap- 

 pearance of those of spinulosa, only they are narrower, and 

 have narrow pinnae. The outline of these latter is narrow 

 lance-shaped, drawn out at the apex, the pinnae having a nar- 

 row tapering form, and the pinnules being oblong-pointed, 

 with rather deep, serrated, marginal notches, the serratures 

 terminating in a fine, somewhat hardened point. 



The midvein of the pinnules is somewhat 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. 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. The stipes has ovate, pale-coloured scales, rather 

 sparingly distributed, and most numerous at the lower part ; 

 and the sori are covered by even-margined, kidney-shaped 

 scales or indusia. 



This plant is found on boggy heaths, generally in company 

 with cristata and spmulosa; it has, however, we are in- 

 formed, been detected where cristata is unknown to exist. 

 As far as we yet know, it is comparatively rare. 



