4:0 BRITISH FERNS. 



which Polypodium angidare, Aspidium angulare, and Poly 

 stichum setiferum, are more commonly in use than the rest 

 It is a strong-growing, tufted stemmed species, sometimes 

 forming large masses. The fronds are lanceolate, from two 

 to four or five feet high, persistent through ordinary winters 

 and in sheltered situations retaining their verdure unim- 

 paired until the new fronds are produced. It is one of the 

 most graceful of all the native species. The stipes, which 

 varies from a third to a fourth of _the length of the entire 

 frond, is very shaggy, with reddish chaffy scales, which 

 scales, though of smaller size, are continued throughout the 

 upper parts of the frond. The fronds are bipinnate, with 

 numerous tapering, distinct pinnae, having their pinnules flat, 

 soirewhat crescent-shaped, from the prominent auricle at 

 the anterior base, often bluntish at the apex, but sometimes 

 acute, always with spinulose marginal serratures, and some- 

 times, in a few of the lower pinnules, with deep lobes, so 

 that the pinnules become pinnatifid. The pinnules are 

 tapered to a broad-angled base, the lines of which usually 

 exceed a right-angle, and they are attached to the rachis of 

 the pinna by a short, distinct, slender stalk, which does not 

 form a line with either margin. The pinnules have branched 

 free veins ; and the sori are generally ranged in a row on 

 either side the midrib, and are covered by a peltate scale or 

 indusium. 



The highly developed form of this species alluded to, as 

 having its basal pinnules deeply lobed, is the variety sub- 

 tripinnatum. It does not differ in any other particular, but, 

 being rather more lax than the other forms, is one of the 

 most elegant of them all. It is not uncommon. The variety 

 decompositum is still more divided in the same way. 



The variety proliferum is another very elegant and highly 

 developed form. This has the pinnules narrowed and atte- 

 nuated, more or less lobed; and the stipes bears above 

 ground little buds, which become young plants. It has beeii 

 found in Devonshire. 



The variety imbricatum is a very remarkable form, differing 

 from the type, in the very narrow linear-lanceolate outline 

 of the frond, as well as in having the pinnules, which arc 

 roundish-oLloug, so closely placed that they overlap each 

 other. It also bears young plants on the stipes above the 

 surface of the soil. It was found in Somersetshire. 



The variety alatum is another exceedingly curious form. 

 In this the fronds are small ; and the pinnules are connected 

 by a very obvious leafy expansion which margins the rachis, 



