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Ceratophyllum demersum
Also called Coontail, Hornworts, Hornwort, Coon's-Tail, Common hornwort, Common Coontail, Coon’s Tail, Hornwort
Rigid hornwort is a fully submerged, free-floating aquatic plant with no true roots, widely grown in ponds and aquariums. It needs still or slow-moving, nutrient-rich water and grows very easily.
Ceratophyllum demersum, commonly called hornwort or coontail, is a species of flowering plant in the genus Ceratophyllum. Ceratophyllum demersum is a submerged, free-floating aquatic plant, with a cosmopolitan distribution, native to all continents except Antarctica. It is a harmful weed introduced in New Zealand. It is also a popular aquarium plant. Its genome has been sequenced to study angiosperm evolution.
This species is often used as a floating freshwater plant in both coldwater and tropical aquaria. Though without roots, it may attach itself to the substrate or objects in the aquarium. Its fluffy, filamentous, bright-green leaves provide excellent cover for newly hatched fish. It is propagated by cuttings. This plant appears to drop all its leaves when exposed to products designed to kill snails. The stems can recover relatively quickly, growing new leaves within a few weeks.
It is frequently used as a model organism for studies of plant physiology. One of the reasons for this is that it allows studies on shoot effects without influence of a root, which often makes interpretation of nutrition and toxicity experiments difficult in terrestrial plants. As it is free floating and therefore does not require a solid substrate, it has been used successfully in the biological life support systems "Aquarack/CEBAS" and "Omegahab" on space flights.
Ceratophyllum demersum grows in lakes, ponds, and quiet streams with summer water temperatures of 15–30 °C and a rich nutrient status. In North America, it occurs in the entire US and Canada, except Newfoundland. In Europe, it has been reported as far north as at a latitude of 66 degrees in Norway. Other reported occurrences include China, Siberia (at 66 degrees North), Burkina Faso and in the Volta River in Ghana (Africa), Vietnam, and New Zealand (introduced). Ceratophyllum demersum grows in still or very slow-moving water.
Spineless hornwort · Prickly hornwort · Soft Hornwort · Hornwort
Text excerpted from the Wikipedia article Ceratophyllum demersum by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
