THE ALPINE BLADDER FERN. 97 



XXVI. THE ALPINE BLADDER FERN. 



Cystopteris regia. 

 (Plate XII., Fig. 2, page 71.) 



LENGTH OF FROND. Four to ten inches. 



GENERAL DESCRIPTION. Roots fibrous, black, wiry, 

 numerous. Rootstock, a small, tufted cormus. Fronds 

 numerous, brittle, herbaceous, delicate, produced in 

 tufts ; stipes ordinarily short ; leafy portion somewhat 

 broadly lance-shaped, bipinnate ; pinnae in opposite 

 pairs upon the rachis or alternate short, ovate, and 

 again divided into bluntly-ovate, deeply-incised pinnules. 

 This fern resembles a rounded form of Cystopteris 

 fragilis. Fructification produced abundantly over all 

 the under-surface of the frond, and consisting of round 

 sori covered by the hood-like indusia, each sorus keep- 

 ing itself distinct from the others. Hence the sori of 

 this species do not become confluent, as frequently do 

 those of Cystopteris fragilis. 



HABITATS. The moist fissures of rocks and the 

 earthy seams of old walls. 



WHERE FOUND. This fern has been discovered in 

 very few localities in Britain, though it is quite possible 

 that it is much more plentiful than is generally supposed. 

 The places where it has been found growing in England 

 are in the counties of Cumberland, Derby, Durham, 

 Essex, and York ; at Saddleback in Cumberland, and 

 at Low Leyton in Essex, in which last-named place it 

 was found upon an old wall from which it has now dis- 

 appeared. In Wales, it is said to have been found at 

 Cwm-Idwal and on Snowdon ; and on Ben Lawers in 

 Scotland. 



