18 FEBNS OF THE LAKE COUNTBY 



producing black fibrous roots. From it spring deli- 

 cate hairy pale-green fronds, to the height, when full- 

 grown, of from six to twelve inches. The stipes is 

 fleshy and very brittle, frequently longer, sometimes 

 much longer, than the leafy part of the frond, having 

 near its base a few small and almost colourless scales. 

 The fronds are triangular, extending to a long narrow 

 point; in the lower part pinnate, but with this di- 

 vision seldom carried beyond the two lowest pairs of 

 branches, those of the upper parts of the fronds being 

 pinnatifid (connected at the base). The pinnae (or 

 leaflets) have an acutely lance-shaped outline and 

 are deeply pinnatifid, usually standing in pairs, oppo- 

 site to each other, the lowest pair drooping toward the 

 root and set on at a short distance from the rest. The 

 united bases of the pairs of the other pinnae when 

 they happen to stand exactly opposite to each other 

 exhibit more or less distinctly a cruciform figure, by 

 which, regard being had also to the general triangular 

 outline and sub-pinnate division, this species may be 

 known from the other Polypodies. The venation con- 

 sists of a slender flexuous midvein (or rib), from which 

 proceed alternate or sometimes opposite veins extend- 

 ing to the margins of the lobes or lobules, either 

 simple or once forked at about half of their length. 

 The veins when simple, or the anterior venules when 

 divided, bear a sorus at a short distance from the edge 

 of the lobule. This almost marginal fructification 

 extends nearly over the whole frond, the sori being 

 small and circular, arranged in series, and often becom- 

 ing confluent in lines. When the fructification is but 



