SPECIES AND VARIETIES OF BRITISH FERNS. 67 



of the branches with subulate two-ribbed teeth ; the 

 fertile stems simple, short, with large crowded sheaths. 

 Plate XX. %. 2. 



2. E. pratense, Ehrhart. — Stems dissimilar, the sterile 



branched, rough, with about twenty ridges, the sheaths 

 of the branches having subulate one-ribbed teeth ; 

 fertile simple, with approximate appressed sheaths. 



3. E. arvense, Linnceus. — Stems dissimilar, the sterile 



branched, slightly rough, with from ten to sixteen 

 ridges, the sheaths of the branches having long-pointed 

 one-ribbed teeth ; the fertile simple, with distant, loose 

 sheaths. 



4. E. sjlvsiticTim, Li7ina;iis. — Stems similar, with about 



twelve ridges, and having loose sheaths terminating 

 in three or four large blunt lobes ; branches deflexed. 

 Plate XX. fig. 3. 



6. E. limosum, Linnccus. — Stems similar, smooth, with 

 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, Ze?2wa?M5, — Stems similar, slightly rough, 

 with from six to eight broad prominent ridges, the 



F 2 



