Ceratophyllales - Ceratophyllaceae (weeds) - (hornwort family)
The order Ceratophyllales belongs to the flowering plants and contains only one family the Ceratophyllaceae and only the genus Ceratophyllum with 4 species. These are aquatic plants and includes coontail (Ceratophyllum demersum), a popular aquarium plant which has become invasive in some regions.
The plants are usually floating on the surface and can reach a length of several metres. The leaves are arranged in whorls. Small males and female flowers are produced on the same plant and fertilization takes place under water.
The following species are currently entered under this family: