SWISS FEBNS. 131 



three feet high, which grows in the circular form of the 

 Male Fern, but has a less scaly stalk and different sori. 

 Fronds twice pinnate, the segments with pointed teeth. 

 Forests. 



A. Alpestre is a variety of the Lady-Fern with very small 

 lobes. 



A. Adiantum-nigrum, Black Spleenwort. Frond from 

 six to twelve inches high, triangular, shining, dark green, 

 twice or thrice pinnate, segments sharply toothed. Warm 

 hills. 



11. Blechnum boreale. — Northern 

 Hard Fern. 



This is remarkable, and distinguished at first glance, from 

 having two kinds of fronds : the barren, lanceolate, with 

 rather broad segments, which approach each other and are 

 from one to two inches long in the middle, gradually taper- 

 ing toward each end ; the fertile, which rise in the middle 

 of the tuft and have only very narrow linear segments, the 

 under part of which is filled by the sori arranged in two 

 lines. Forests, boggy ground. 



9 ♦ 



