224 THE FERN ALLIES. 
long acute one-ribbed teeth ; fertile simple short with 
few distant sheaths. In damp meadows and fields. 
Stems similar, simple or branched. 
4. E. sylvaticum, Linrueus. Stems with about 
12 ridges; branches deflexed; sheaths loose, termi- 
nating in 3-4 blunt lobes. In damp woods. 
5. E. limosum, Linneeus. Stems smooth with nu- 
merous slight ridges; branches short erect few, often 
wanting; sheaths green close with 16-20 sharp- pointe 
dark teeth. In marshy places and ditches. 
6. E. palustre, Linn&us. Stems roughish with 
6-8 broad prominent ridges ; branches erect ; sheaths 
pale loose with acute wedge-shaped brown-tipped 
teeth. In boggy or marshy places. 
7. E. Macliaii, Newman. Stems very rough with 
8-12 ridges, almost or quite branchless ; sheaths close, at 
first green, with a black band, ultimately wholly black 
with narrow subulate persistent teeth. In mountain glens. 
8. E. hyemale, Linnaeus. Stems very rough with 
14-20 ridges, branchless ; sheaths close whitish banded 
with black at top and bottom, their teeth slender deci- 
duous. In damp woods. 
9. E. variegatum, Weber and Mohr. Stems very 
rough with 4-10 ridges, almost or quite branchless: 
sheaths slightly enlarged upwards, green below black 
above, with obtuse teeth tipped by a deciduous bristle. 
On sandy coasts, and wet sandy places. E. Wilsoni, 
Newman, is a form with less rough taller stems. 
