Virginia Tech Weed Identification Guide

Coontail or Hornwort: Ceratophyllum demersum

Weed Description:  An aquatic annual weed that is submersed and has the overall appearance of a ‘coon’s tail’.   This weed is capable of forming large colonies in fairly deep water of lakes and ponds and is found throughout the southeastern United States.
Leaves:  All parts of the plant, including the leaves, are rough to the touch.  Leaves are submersed, finely dissected, and occur in whorls of 5 or more.  Individual leaves are linear in outline, to inch long, and are toothed along one margin only.  Leaves become more and more crowded toward the stem tip.
Stems:   Rough feeling, branched, reaching 15 feet or more in length.  Stems are either floating free or attached to the substrate below via rhizoids.
Flowers:  Small, solitary, without a stalk, and occur at the leaf bases (leaf axils).  Flowers are inconspicuous and have no sepals and petals.  Flowers also remain submersed throughout the year.
Fruit:   An achene.
Identifying Characteristics: Submersed aquatic weed that resembles a coon’s tail.  The toothed margin along one side of the leaves of coontail help to distinguish this from most other submersed aquatic weeds.