94 



THE BOOK OF CHOICE FERNS. 



all being found growing naturally at high elevations. With the exception of 

 C. montana., which is provided with underground creeping rhizomes, all the 

 Cystopterises produce their slender fronds in great abundance either from 

 a closely-tufted crown or from shortly-decumbent rhizomes. On account of 

 their delicate appearance, all are well adapted for pot- culture, either under 

 glass, in a cold frame, or without glass protection, in a sheltered position. 

 All the known species and varieties are naturally of a thoroughly deciduous 

 nature, losing their fronds early in the autumn and remaining dormant until 

 about April, during which period their crowns must not be allowed to get' 

 completely dry. When planted out, a compost of about equal parts of fibrous 

 peat, loam, and leaf mould is the one which suits all Cystopterises best. For 

 pot-culture it is advisable to add to this mixture a small proportion of old, 

 crumbled mortar or broken limestone, and also to pay special attention to 

 the drainage. 



The Bladder Ferns are usually propagated during March and April by 

 division of the crowns, wherever more than one has formed ; they are also 

 easily raised from spores sown in autumn in a cold frame. C. bulhifera^ 

 however, is more readily increased by means of the bulbils produced along its 

 rachises (stalks of the leafy portion of the frond), which, having fallen to the 

 ground, soon emit a few slender roots and send up some rudimentary fronds, 

 producing perfectly-developed foliage during the second year. 



Species and Principal Varieties. 



C. alpina — al-pi'-na (mountain -loving), Desvaux. 



This pretty little Fern, also known as C. regia, is one of the rarest 

 species indigenous in Great Britain — so rare, indeed, that for a long time it 

 appeared very doubtful if it could be classed among the British species ; but 

 that it is one of our native Ferns is quite certam now. In the second edition 

 of Ray's " Synopsis," published in 1696, we find that a Mr. Lhwyd first 

 discovered it on Snowclon. Later on it was again found in Wales, this time 

 by a Mr. Grriffiths, on Cwm Idwell ; while Mr. W. Christy met with it at 

 Knaresborough, where it was growing on rocks. It was also found, in 1793, 

 at Low Leyton, Essex, by a Mr. Forster, who notified his discovery at the 

 time in Symon's " Synopsis." The Alpine Bladder Fern was again found at 



