80 BRITISH FERXS. 



a close tufted stem, producing from its crown numerous 

 bright green fronds, usually four to six, but sometimes as 

 much as ten inches high. These grow up in May, and die 

 away in autumn. Their form is lanceolate, the mode of di- 

 vision bipinnate, with the pinnules so deeply pinnatifid as to 

 render them almost tripinnate. The stipes is short, smooth, 

 and scaly at the base. The pinnae are nearly opposite, with 

 a winged rachis, ovate, divided into bluntly ovate pinnules, 

 these latter being deeply cleft, almost down to their midvein, 

 into short, blunt, linear lobes, which are either entire, or 

 have two or three blunt teeth. The midvein of the pin- 

 nules is nearly straight, with a venule, simple or divided, 

 branching off to each lobe, one branch extending to the point 

 of each marginal tooth. The small roundish sori are rather 

 numerous, but not confluent, borne near the margin, and 

 covered by a concave membranous indusium. 



This species, which may be cultivated without difficulty 

 in pots, under shelter, provided they are guarded against the 

 effects of damp in winter, has been found on an old wall at 

 Leyton, in Essex. It occurs in the alpine parts of southern 

 Europe. 



MOUNTAIN BLADDER FERN. 



The mountain Bladder Fern is Cystopteris montana. Its 

 synonyms are Polypodium montanum, Aspidium montanum, 

 Cyathea montana, Cystopteris Attioni, and Cystopteris myr- 

 rhidifplium. 



This is the rarest of our native Ferns. It is a small 

 species, growing with a slender creeping scaly stem. The 

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

 outline, from the great development of the lowest pair of 

 pinnae ; tripinnate in the lower part, and bipinnate upwards, 

 the pinnae spreading, and standing opposite in pairs, the 

 lowest pair considerably larger than the next above, and un- 

 equally developed, the inferior side being very much larger 

 than the superior. The lower pinnae, on the inferior side, 

 are first divided into ovate or lanceolate pinnules, and these 

 are again cut into a second series of pinnules, of an ovate or 

 oblong form, these ultimate pinnules being coarsely and 

 irregularly notched or toothed ; on the upper side, the pin- 

 nules correspond with the secondary pinnules of the lower 

 side. The inferior pinnules of the next pair of pinnae also 

 correspond in size, outline, and subdivision with the secon- 

 dary pinnules of the lower pinnae ; and above this the parts 

 become gradually smaller and less divided up to the apex of 



