180 HISTORY OF BRITISH FERNS. 



The usual forms of this species occur abundantly in 

 moist mountainous districts, and also on walls, but gener- 

 ally in moist rocky situations throughout the United 

 Kingdom, Ireland excepted, where it is comparatively 

 rare. The same species is very widely dispersed in various 

 parts of the world. The varieties are more rare. Cysto- 

 pteris fragilis may be said to have rather a preference to 

 limestone. Under cultivation it is one of the most 

 manageable of the smaller sorts, growing freely on rock- 

 work or in pots. Its fronds are produced very early in 

 spring, are often renewed during summer, and continue to 

 grow up in succession until the frosts cut them off. Being 

 so very delicate in texture, the first frosts which have 

 access to them do this. 



The names of Cyathea fragilis, C. cynapifolia, C. an- 

 thriscifvlia, G. dentata ; Cystea fragilis, C. angustata, 

 C. dentata ; Polypodium fragile, P. cynapifoliam, P. 

 antkriscifolium, P. dentatum, P. rhwticum ; Aspidium 

 fragile, A. dentatum, and A. rhwticum, have been given 

 by various authors to the different forms of this variable 

 species. 



