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Coontail
Species:
C. demersume
Common Name:
Coontail
Conservation Status:
LC
Subspecies:
C. ceratophyllum subsp. demersum
Subspecies:
C. ceratophyllum subsp. platyacanthum
Subspecies Variety:
Ceratophyllum demersum var. apiculatum
Subspecies Variety:
C. ceratophyllum subsp. platyacanthum
Subspecies Variety:
Ceratophyllum demersum var. inerme
Subspecies Variety:
Ceratophyllum demersum var. quadrispinum
Subspecies Form:
Ceratophyllum demersum f. missionis
Description:
Ceratophyllum demersum, commonly known as coontain, coon′s tail, hornwort, and rigid hornword, is a species of flowering plant. This species is a submerged, free floating aquatic plant with a cosmopolitan distribution, meaning this species is native to all continents except Antarctica. This species is a popular aquarium plant.
An aquatic plant, Ceratophyllum demersum has stems that reach lengths of 3 to 10 feet (1–3 meters), with numerous side shoots making a single specimen appear as a large, bushy mass. The leaves are produced in whorls of six to twelve, each leaf .3 to 1.5 inches long (8–40 mm), simple, or forked into two to eight thread-like segments edged with spiny teeth; they are stiff and brittle.
This species is monoecious, with separate male and female flowers produced on the same plant. The flowers are small, 3/32 inch long (2 mm), with eight or more greenish-brown petals; they are produced in the leaf axils.
The fruit is a small nut 3/16 inch long (4–5 mm), usually with three spines, two basal and one apical, 1/16 to 1/2 inch long (1–12 mm). Plants with the two basal nut spines very short are sometimes distinguished as Ceratophyllum demersum var. apiculatum (Cham.) Asch., and those with no basal spines sometimes distinguished as Ceratophyllum demersum var. inerme Gay ex Radcl.-Sm.
This species can form turions, called wintering buds which sink to the bottom of the water and stay there during the winter before forming new plants in spring.
Habitat:
Ceratophyllum demersum grows in lakes, ponds, and quiet streams with summer water temperatures of 60-86 degrees F, (15–30 °C) and a rich nutrient status. This species grows and occurs in still or very slow moving water.
Range:
In North America, this species 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).
Hornwort is a declared weed under the Tasmanian Weed Management Act 1999 in Tasmania, Australia, and is classed as an unwanted organism and harmful weed in New Zealand that has been introduced there.
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