54 WAYSIDE AND WOODLAND FERNS. 



character. The name was not borrowed from the Greek as 

 usual, but chosen to immortalize and do honour to his contem- 

 porary, Joseph Woods, best known to the public as the author 

 of The Tourisfs Flora. 



The indusium in Woodsia is underneath the sorus, thus, as 

 Francis expresses it, at first inclosing the mass of spore-cases 

 in a bag ; it then becomes split into numerous segments which 

 look like hairs interspersed with the capsules, and were so con- 

 sidered until Brown showed their true nature (Plate 17). The 

 worn-out fronds break off by a clean articulation or joint above 

 the base of the stipes, just as the leaves of forest trees are 

 detached in autumn. In this way a palisade of frond stumps 

 is left around every crown. 



There are only two native species, and these are by some 

 authorities considered as forms or sub-species of one. Many 

 writers, however, have dealt with them as distinct, and we shall 

 treat them separately here, although we agree more with those 

 who regard Woodsia ilvensis as a sub-species of IV. hyperborea. 



Alpine Woodsia (Woodsia hyperborea). 



This is quite a small fern, with a stout rootstock and tufted 

 fronds, which grows in the clefts of wet alpine rocks. The 

 fronds are from one to four inches long with a polished reddish 

 stipes, sparsely clothed with slender rust-coloured scales. The 

 leafy portion is lance-shaped in general outline, but broken up 

 into oval or oblong pinnae, which are sparingly lobed and rather 

 distant one from another. The lower pinnae have rounded teeth 

 at their base. The back and margins of the frond are furnished 

 with distant hairs. The fronds are shed at the approach of 

 winter. (Plate 57.) 



The sori are round, placed near the margins of the pinna- 

 lobes, at first seated in a thin cup, the indusium, whose edges 

 are torn into hair-like segments. This tearing process extends 



