Translations:Adventist Youth Honors Answer Book/Nature/Ferns/33/en

Equisetum palustre (Marsh Horsetail)

E. palustre is a perennial horsetail, growing between 10 to 50 centimeters (4" to 20"), in rare cases up to 1 meter (3'). Its fertile shoots, which carry ears, are evergreen and shaped like the sterile shoots. The rough, furrowed stem is 1 to 3 mm in diameter with usually 8 to 10 ribs, in rare cases 4 to 12. It contains whorled branches. The tight-fitting sheaths end in 4 to 12 teeth. The lower sheaths are dark brown and much shorter than the sheaths of the main shoot. The central and vallecular are about the same size, but the carinal channels are much smaller. The central channels measure about one sixth of the diameter of the stem.