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Ceratophyllum Linnaeus. Hornwort, Coontail.

Key to Ceratophyllum

A genus of about 6 species, aquatic herbs, of cosmopolitan distribution.

ID notes: Ceratophyllum is sometimes mistaken for superficially somewhat similar, aquatics, such as Cabomba (Cabombaceae), Utricularia (Lentibulariaceae), and Myriophyllum (Haloragaceae). Cabomba has the leaves opposite (rather than whorled), dichotomously divided (like Ceratophyllum), but the divisions lacking the marginal denticles of Ceratophyllum, and on a 1-3 cm long petiole (vs. sessile or on a petiole 0-2 mm long). Utricularia has the leaves sometimes dichotomously divided, but the divisions are usually irregular, the leaves are alternate (in most species), and bladder traps are present. Myriophyllum has the leaves pectinately rather than dichotomously divided.

Ref: Les (1985); Les (1986); Les (1988a); Les (1988b); Les (1988c); Les (1989); Les (1997) In Flora of North America Editorial Committee (1997); Les In Kubitzki, Rohwer, & Bittrich (1993); Szalontai et al. (2018); Wilmot-Dear (1985). Show full citations.

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