WOODSIA HYPERBOREA. 273 
WOO'DSIA HYPERBO'EEA. 
THIS has beeu called Acrostichum alpinum, Ceterach 
alpinum, Polypodium hyperboreum, P. Arvonicum, and 
Woodsia alpina. By some botanists it is considered 
merely a variety of Woodsia Ilvensis. In English it is 
known as the Alpine Woodsia, Rounded- leaved Woodsia, 
and Hairy Polypody. 
Its roots are fibrous, very deeply penetrating, black, 
and tufted. Fronds narrow spear-head shaped in their 
general outline ; the lower third of each stem is without 
leaflets, but having a few hairs and light brown chaffy 
scales. The stem is united to the root by a joint, from 
which it falls off when the frond decays in autumn. 
Leaflets in pairs, quite or nearly opposite, smooth, tri- 
angular in their general outline, but with the angles 
rounded; deeply lobed and scolloped; mid-vein not 
strongly marked, and its side-veins are simple or only 
two-forked, reaching nearly to the edge of the lobes, and 
not far from the end of these side-veins is the fructi- 
fication. This consists of from six to ten circular masses 
on each leaflet; they are large, light brown, and usually 
increase in size until they run together. The cover 
(indusium) of each mass is divided into such numerous 
segments that the fructification seems imbedded in hairs. 
This appears fully in our woodcut of Woodsia Ilvensis. 
In England and Ireland this very rare Fern has never 
been found. 
In Wales it has been discovered at Clogwyn-y- 
