182 HISTORY OF BRITISH PERNS. 



tlie eflfects of damp in winter, has been found on an old 

 wall at Leyton, in Essex. Its claim to aboriginality is 

 strongly suspected, a small, much-divided form of Cysto- 

 pteris fragilis being supposed to have been mistaken for 

 it. The Scotch and Welsh plants which have been called 

 Cystopteris alpina are probably open to this objection, but 

 the Essex plant is no doubt genuine ; and fronds of the 

 true plant have been communicated by Mr. Shepherd of 

 Liverpool, as having been gathered in Derbyshire and 

 Yorkshire ; and we have seen others from the Lake district. 

 It occurs in the alpine parts of southern Europe. 



Cystopteris alpina is another name for this elegant plant, 

 which has also been called Cyathea rec/ia and Cyathea 

 incisa, Cystea regia, Polypodium reyinm, Polypodium 

 alpinum, Aspidium regium, and Polypodium trifidum. 



Cystopteris montana, LiiiJc. 



The 3Iountain Bladder-Fern. (Plate XIV. fig. 2.) 



This is one of the rarest of our native Ferns, and hence 

 is a plant of great interest. It is a small species, growing 

 with a slender creeping stem, by the division of which it is 

 increased. The fronds, which grow up from this caudex, 

 are from four to six or eight inches high, triangular in 



