hornwort

from WordNet (r) 3.0 (2006)

hornwort
    n 1: any aquatic plant of the genus Ceratophyllum; forms
         submerged masses in ponds and slow-flowing streams
    2: liverworts with slender hornlike capsules

from The Collaborative International Dictionary of English v.0.48

Hornwort \Horn"wort`\, n. (Bot.)
   An aquatic plant ({Ceratophyllum}), with finely divided
   leaves.
   [1913 Webster]

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