48 BRITISH FERNS. 



markably so ; less frequently it extends downwards to the 

 pair of pinnae next above the basal ones. The spots of spore- 

 cases are covered by a kidney-shaped scale or indusium, 

 having an entire margin, and become mature in August and 

 September. 



The variety uliginosa is exactly intermediate in its general 

 appearance and characters between the normal form of the 

 species and the variety spinulosa. It forms a stout creeping 

 crown or root-stock,_ having a tendency to multiply by late- 

 ral offshoots. The stipes has ovate pallid scales. The fronds 

 grow nearly erect to the height of from two to three feet ; 

 these erect fronds bear the fructification. Other fronds, 

 however, are produced, which are barren, and these do not 

 grow so erect, nor put on the same form as the fertile ones ; 

 but closely resemble those of cristata itself, the fertile ones 

 having much the appearance of those of the var. spinulosa, 

 only that they are narrower, and have narrow pinnse. The 

 outline of these latter is narrow lance-shaped, the pinn<B 

 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 

 sori 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. Some- 

 times 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. 



The variety spinulosa is also an erect-growing kind, with 

 a stout creeping stem or root-stock, which becomes 

 branched, so that several crowns are generally found forming 

 one mass. The stipes is sparingly furnished with semi- 

 transparent scales of a bluntly ovate form. The fronds grow 

 from one to three feet high, and are bipinnate, the pinnaa 

 having an obliquely tapering form from the inferior pinnules 

 being larger than the superior ones ; this is most obvious at 

 the base of the fronds, where the pinnae are broader than 

 they are towards the apex. The lower pinnules on the 

 basal pinnae are of an oblong form, somewhat narrowing 

 upwards, the margins deeply incised, the lobes being ser- 

 rated, and the teeth somewhat spinulose. 



This species occurs only on boggy heaths, and that in but 

 few places in Britain, confined, we believe, to the counties 

 of Nottinghamshire, Cheshire, Norfolk, and Suffolk. The 

 var. uliginosa is usually found in company with it ; while 



