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Name derivation:

"Horn leaf" -- Horn Cerato- leaf -phyllum (Greek). Commonly called "coon tail" or "horn wort" -- unfortunately the latter confuses students who may incorrectly associate Ceratophyllum with the ancestral non-vascular hornworts classified as bryophytes.

Classification:

Ceratophyllum Linnaeus 1753.

Order Ceratophyllales;  Family Ceratophyllaceae

Morphology:

Bifurcate leaves arise in whorls from stem. 

Lacks roots.

Imperfect flowers.  Pistillate (female) flowers have specialized through reduction (Iwamoto et al.  2003). Both staminate and pistillate flowers are inconspicuous, and lack sepals and petals.

Fruits have two spurs and a beak, and bear a single seed.

Similar genera:

 

Habitat:

Widely distributed globally, native to all continents except Antarctica.  Freshwater lakes and streams throughout N. America.

 

References:

Iwamoto, A., A. Shimizu, and H. Ohba  2003.  Floral development and phyllotactic variation in Ceratophyllum demersum (Ceratophyllaceae).  American J. Bot. 90:1124-1130.

Linnaeus, C.  1753.  Species Plantarum 2:992.