Ceratophyllum demersum, commonly known as hornwort, rigid hornwort, coontail, or coon's tail, is a species of Ceratophyllum. It is a submerged, free-floating aquatic plant, with a cosmopolitan distribution, native to all continents except Antarctica. It is a harmful introduced weed in New Zealand. It is also a popular aquarium plant.
An aquatic plant, Ceratophyllum demersum has stems that reach lengths of 1–3 m (3–10 ft), with numerous side shoots making a single specimen appear as a large, bushy ...