108 
BRITISH FERNS. 
3. E . arvense. Sterile stems branched, slightly rough, 
with from ten to sixteen ridges; fertile ones 
simple, with distant, coarse sheaths, having long 
pointed teeth. 
4. E. sylvaticum. Stems all of one form, with about 
twelve ridges, and having loose sheaths, with 
about four blunt lobes ; branches drooping. 
5. E . limosum . Stems similar, smooth, with numerous 
slight ridges ; the sheaths green, close, having 
from sixteen to twenty sharp-pointed dark- 
coloured teeth ; branches short, few, often 
absent. 
6. E. palustre. 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. hyemale. 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. 
8. E. trachyodon. Stems similar, very rough, branch- 
ing from the joints at the base ; sheaths with 
from six to thirteen narrow teeth. 
9. E. variegatum . Stems similar, very rough, with from 
four to ten ridges ; sheaths slightly enlarged, 
green below, black above, with obtuse teeth, 
tipped by a deciduous bristle ; almost branch- 
less. 
