jagged, deciduous lobes or segments, to which section our pre- 
sent plant belongs; and 3. Woodsia (vera), Br., involucres mi- 
nute, covered and concealed by the capsules, the long hairs of 
the margin only projecting beyond the sorus. To this belong 
our two British species, W. hyperborea and Ilvensis. But so 
difficult is the exact structure of this minute and very fragile 
organ to be seen, that some able modern botanists still place the 
species in question in Polypodium. 
Puate 43. Fertile plants of Woodsia (Perrinia) obtusa, Hook.,—nat. size. 
Fig. 1 and 2. Pinnules, with sori,—magnified. 3. Involucres, spread, most of 
the capsules removed, showing the receptacle,—more magnified. 
