58 HISTORY OF BRITISH FERNS. 



numerous slight ridges, the sheaths green, close, 

 with from sixteen to twenty sharp-pointed dark- 

 coloured teeth; branches short, few, often wanting. 



6. E. palustre, Linn&us. Stems similar, slightly 



rough, with from six to eight broad prominent 

 ridges, the sheaths pale, loose, with acute wedge- 

 shaped, brown-tipped teeth; branches erect. 



7. E. Mackaii, Newman. Stems similar, very rough, 



with from eight to twelve ridges, and having close 

 sheaths, which alternately become wholly black, 

 and have narrow subulate teeth ; almost branchless. 



8. E. hyemale, Linnatts. Stems similar, very rough, 



with from fourteen to twenty ridges, and having 

 close whitish sheaths banded with black at the top 

 and bottom ; the teeth slender, deciduous ; almost 

 branchless. Plate XX. fig. 1. 



9. E. variegatum, Weber et Mokr. Stems similar, very 



rough, with from four to ten ridges, and having 

 slightly enlarged sheaths, green below, black 

 above, with obtuse teeth tipped by a deciduous 

 bristle ; almost branchless. 

 b. Wilsoni. Stems less rough, taller. 



