^58 



OUR COMMON FERNS. 



The Lastreas (Nephrodiums). 



As a necessary preliminary to a knowledge of the varietal 

 forms of our British Ferns, whether as natural "sports" 

 or " mutants," or as the result of selective cultivation 

 through the spore, is a familiarity with the common forms 

 which constitute Nature's raw material, and as we cannot 

 expect all our readers to be experts, we intend in this and 

 succeeding issues to give a description of each normal 

 species so as to permit of its discrimination from others. 

 Starting with a genus which embraces the commonest or 

 most prevalent types we begin with 

 The Lastreas (Nephrodiums), or Buckler Ferns. 



This genus is represented in Great Britain by six definite 

 species, viz. L. filix mas, the common J\Iale Fern, L. 

 montana (Oreopteris), the Alountain Buckler Fern or Lemon- 

 scented Fern,L. dilatata, the Broad Buckler Fern, L. amula, 

 the Hay-scented Fern, L. rigida, the Limestone Buckler 

 Fern, L. thelyptevis, the iNIarsh Buckler Fern, and three 

 indefinite species, L. spiiuilosa, L. uliginosa, and L. cvistata. 

 In their fertile state, all those may be distinguished by their 

 spore heaps being protected by a kidney shaped indusium, 

 attached to the frond at the point of indentation of this 

 cover, this being the generic character which gives the 

 name of Nephvodittin {Nephron, Greek for kidney), and also 

 the popular name of Buckler Fern to the genus. By 

 remembering this fact, we can consequently immediately 

 determine, at any rate, the genus or family by examining the 

 fertile frond backs. Each species, however, has its individual 

 form of frond. In the common ]\Iale Fern (L. filix mas) 

 the fronds grow erect and form a shuttlecock-like circle 

 round a scaly brown caudex or rootstock built up of the 

 persistent bases of old and otherwise perished fronds. In 

 the centre or heart of this caudex there are formed the 

 future fronds during the season, only one circlet rising as a 

 rule during the year. This species produces offsets by buds, 



