Ceratophyllum demersum
Encyclopedia
Ceratophyllum demersum (hornwort, rigid hornwort, coontail, or coon's tail) is a species of Ceratophyllum
. It is a submerged, free-floating aquatic plant
, native to North America
but nowadays having a cosmopolitan distribution
in temperate and tropical regions. It is also a popular aquarium plant.
are produced in whorls of six to twelve, each leaf 8–40 mm long, simple, or forked into two to eight thread-like segments edged with spiny teeth; they are stiff and brittle. It is monoecious
, with separate male and female flower
s produced on the same plant. The flowers are small, 2 mm long, with eight or more greenish-brown petals; they are produced in the leaf axils. The fruit
is a small nut 4–5 mm long, usually with three spines, two basal and one apical, 1–12 mm long. 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. It can form turions: buds that sink to the bottom of the water that stay there during the winter and form new plants in spring.
. In Europe, it has been reported as far north as at a latitude of 66 degrees in Norway. Other reported occurences include China, Siberia
(at 66 degrees North), Burkina Faso
(Africa), Vietnam, and New Zealand.
and cyanobacteria (blue-green algae). Its dense growth can outcompete native underwater vegetation, leading to loss of biodiversity
. In New Zealand, it has caused problems with hydroelectric power plants.
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 green leaves provide excellent cover for newly-hatched fish. It is propagated by cuttings.
In aquaria 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.
Hornwort is a prohibited plant in Tasmania, Australia.
Ceratophyllum
Ceratophyllum is a cosmopolitan genus of flowering plants, commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions...
. It is a submerged, free-floating aquatic plant
Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...
, native to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
but nowadays having a cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
in temperate and tropical regions. It is also a popular aquarium plant.
Description
Ceratophyllum dersum grows in still or very slow-moving water. The stems reach lengths of 1–3 m, with numerous side shoots making a single specimen appear as a large, bushy mass. The leavesLeaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are produced in whorls of six to twelve, each leaf 8–40 mm long, simple, or forked into two to eight thread-like segments edged with spiny teeth; they are stiff and brittle. It is monoecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, with separate male and female flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s produced on the same plant. The flowers are small, 2 mm long, with eight or more greenish-brown petals; they are produced in the leaf axils. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a small nut 4–5 mm long, usually with three spines, two basal and one apical, 1–12 mm long. 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. It can form turions: buds that sink to the bottom of the water that stay there during the winter and form new plants in spring.
Distribution and habitat
Ceratophyllum demersum grows in lakes, ponds, and quiet streams with summer water temperatures of 15-30 °C and a rich nutrient status. It can survive It is native in North America, but it has spread worldwide as a result of its use as an aquarium and pond plant. In North America, it occurs in the entire US and Canada, except NewfoundlandNewfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
. In Europe, it has been reported as far north as at a latitude of 66 degrees in Norway. Other reported occurences include China, Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
(at 66 degrees North), Burkina Faso
Burkina Faso
Burkina Faso – also known by its short-form name Burkina – is a landlocked country in west Africa. It is surrounded by six countries: Mali to the north, Niger to the east, Benin to the southeast, Togo and Ghana to the south, and Côte d'Ivoire to the southwest.Its size is with an estimated...
(Africa), Vietnam, and New Zealand.
Ecology
C. demersum has allelopathic qualities as it excretes substances that inhibit the growth of phytoplanktonPhytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
and cyanobacteria (blue-green algae). Its dense growth can outcompete native underwater vegetation, leading to loss of biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
. In New Zealand, it has caused problems with hydroelectric power plants.
Cultivation and uses
This species is often used as a floating freshwaterFreshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
plant in both coldwater and tropical aquaria
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
, though without roots, it may attach itself to the substrate
Substrate (aquarium)
The substrate of an aquarium refers to the material used on the tank bottom. It can affect water chemistry, filtration, and the well-being of the aquarium's inhabitants, and is also an important part of the aquarium's aesthetic appeal...
or objects in the aquarium. Its fluffy, filamentous, bright-green green leaves provide excellent cover for newly-hatched fish. It is propagated by cuttings.
In aquaria 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.
Hornwort is a prohibited plant in Tasmania, Australia.