188 HISTORY OF BRITISH FERNS. 



family. The Alpine Woodsia, like its congener, grows in 

 a tufted manner, sending up several fronds from the crown, 

 from the base of which the dark-coloured wiry roots are 

 protruded. In form these fronds are longish and compara- 

 tively very narrow, almost linear, as it is termed ; and they 

 are pinnately divided into several roundish triangular pinnaa, 

 which are shallowly lobed on the margin, and are usually 

 set on alternately along the opposite sides of the stalk or 

 rachis ; those towards the lower part are usually placed at 

 a greater distance apart than those near the upper end. 

 They are nearly smooth on the surface, and, in tliis respect, 

 unlike those of the kindred species, which have a much 

 more hairy appearance ; small hair-like scales, in company 

 with hairs, are however present in this species. The mid- 

 vein of the pinnae is indistinct, and throws out veins 

 into each lobe, these veins being more or less branched 

 according to the size of the lobes. The sori are placed 

 near the extremity of the veins, and are often abundantly 

 produced, so as to become crowded on the pinnae. 



The Alpine Woodsia is also named W. hyperborea, and 

 ■formerly Acrostichum alpinum, Acrostichum hyperboreum, 

 , Folypodium hyperboreum, and Polypodium arvonicum. 



The two species of Woodsia are, in Great Britain, found 



