. 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. fig. 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. sylvaticum, Linnceus.* — Stems similar, with about 
twelve ridges, and having loose sheaths terminating 
in three or four large blunt lobes ; branches deflexed. 
Plate . XX. fig. 3. 
5. E. limosum, Linnceus. — 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, — Stems similar, slightly rough, 
with from six to eight broad prominent ridges, the 
F 2 
