Ceratophyllum demersum — Details

Rigid Hornwort learn more about names for this taxon

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Overview

Comprehensive Description

Description

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This is a submerged or floating aquatic plant (about ½-12' long) that branches at right angles (90°). The jointed stems are pale green to reddish purple, glabrous, and fragile, often dividing into smaller segments. Along these stems, there are whorls of 5-14 divided leaves that curve upward; these leaves are 1-4 cm. long. The leaves are more crowded toward the growing tips of stems than elsewhere; they are medium to dark green and glabrous. Both stems and leaves have a tendency to be somewhat stiff and brittle, especially when they are coated with lime in calcareous water. Each leaf divides dichotomously into 2-4 segments (rarely more); these segments are narrowly linear (up to 0.5 mm. across) and flattened. Each leaf segment is conspicuously toothed along one side, while it is smooth (entire) on the other side. Coontail is monoecious, forming male (staminate) and female (pistillate) flowers on the same plant. Both types of flowers are produced in the axils of the leaves and they are sessile. Female flowers occur individually, while male flowers occur either individually or in pairs. Both types of flowers are very small in size (about 2 mm. in length), and they have involucres consisting of 8-14 floral bracts that surround the reproductive organs. These bracts are translucent and broadly oblong; their tips are truncate and fringed. There are neither sepals nor petals. Each female flower has a single pistil with a long slender style, while each male flower has 8-14 anthers that are sessile or nearly so (very short or absent filaments). The blooming period occurs intermittently during the summer and early autumn. Cross-pollination is accomplished through water currents. However, only a few flowers, if any, are produced by individual plants. The female flowers are replaced by 3-spined achenes. The body of each mature achene is 4-6 mm. long, ovoid in shape, slightly flattened, and wingless along its sides. Each achene has 2 basal spines and a single spine at its apex; these spines are 0.5-12.0 mm. in length and they are either straight or curved. Coontail has no real root system, although it is able to anchor itself in mud or sand through either lodged stems or the development of modified leaves. By late autumn, winter turions (tight buds of leaves) develop at the tips of stems that sink to the bottom of  a body of water, where they remain until spring of the following year. Growth and development begin again with the return of warmer weather. In addition to its achenes and winter turions, Coontail reproduces vegetatively whenever its stems divide into smaller segments.
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Description

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Submerged aquatic herb. Stems up to 3m long and 2 mm in diameter, longitudinally grooved. Leaves in whorls of 7-11, 8-40 mm long, filiform, forked 1-2(3) times; margin with spine-tipped teeth, particularly in the apical segments. Flowers axillary, unisexual on the same plant; male flowers in many 1-3-flowered clusters per branch; female flowers solitary, few per branch. Fruit ovoid, ellipsoid to obovoid with an apical spine and 2 prominent basal spines, and raised dark spots on the surface.
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Distribution

Range and Habitat in Illinois

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The native Coontail is occasional to common throughout Illinois. This species is native to a wide area of North America, from where it has spread to other parts of the world. Habitats include quiet inlets of lakes, ponds, rivers with slow-moving currents, marshes, and springs. Generally, Coontail is typically found in bodies of water with muddy bottoms, although it also occurs where the water bottom contains some sand or rocky material. Sometimes Coontail is cultivated as an aquarium plant. It has also been introduced deliberately into polluted bodies of water in bioremediation projects because of its ability to absorb suspended particles of chromium, lead, arsenic, and other chemicals.
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Distribution in Egypt

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Nile and Mediterranean regions, eastern desert (along Suez Canal).

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Global Distribution

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Cosmopolitan.

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Localities documented in Tropicos sources

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Ceratophyllum demersum var. apiculatum (Cham.) Asch.:
Brazil (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.
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Localities documented in Tropicos sources

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Ceratophyllum tuberculatum Cham.:
India (Asia)

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Localities documented in Tropicos sources

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Ceratophyllum chilense Leyb.:
Chile (South America)

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Localities documented in Tropicos sources

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Ceratophyllum oxyacanthum Cham.:
Germany (Europe)

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Localities documented in Tropicos sources

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Ceratophyllum demersum L.:
Botswana (Africa & Madagascar)
Canada (North America)
United States (North America)
Zimbabwe (Africa & Madagascar)
Zambia (Africa & Madagascar)
Bolivia (South America)
China (Asia)
Peru (South America)
Panama (Mesoamerica)
Mozambique (Africa & Madagascar)
Madagascar (Africa & Madagascar)
Malawi (Africa & Madagascar)
Mexico (Mesoamerica)
Honduras (Mesoamerica)
Guatemala (Mesoamerica)
Gabon (Africa & Madagascar)
Brazil (South America)
Colombia (South America)
Ecuador (South America)
Venezuela (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.
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Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; worldwide.
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Worldwide distribution

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Subcosmopolitan in temperate and tropical regions.
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Range Description

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This species is a cosmopolitan and occurs from the Azores and Europe (Castroviejo et al. 1987, Preston and Croft 1997, Gardenfors 2010, WCSPF 2010) east through the Middle East and the Indian subcontinent to east and southeast Asia (Cook 1970). It occurs in Africa north and south of the Sahara including Madagascar, as well as Australasia and north, central and south America. It is apparently introduced in Mauritius, New Zealand and Hawaii (World Checklist of Selected Plant Families 2010). The species has been recorded along the Mekong River in Thailand, Lao PDR, Cambodia and Viet Nam.

In China (Flora of China; eFlora 2011) this species is widespread throughout the country; it has been recorded from a number of provinces (Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jilin, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang), and expected to be reported from additional provinces.

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National Distribution

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Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

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Polish Exclusive Economic Zone
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Distribution: Cosmopolitan
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Physical Description

Morphology

Description

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Much branched, rootless, submerged, aquatic plants, 15-60 (-90) cm long. Leaves whorled, 1-4 times dichotomously branched, minutely toothed at irregular intervals, often terminated by 1 or 2 sharp bristles. Flowers minute, solitary, axillary, unisexual, male and female flowers at different nodes. Perianth segments 6-15, upto 1 mm long, connate at the base, each segment terminated by 2 bristles. Male flowers consisting of 8-30 stamens, spirally arranged on a convex receptacle, narrowed into the base, subsessile, apex terminated by two spinous incurved processes; anthers erect, 2-lobed, pollen elliptical or round. Female flower consists of a sessile carpel, ovary 1-celled, 1-ovuled, style simple, stigma oblique, style elongating in fruit forming the apical spine. Fruit a nutlet, 3.5-4 mm long, 2.5-3 mm broad (excluding spines), sessile with persistent perianth, ovoid, compressed, provided with 3 spines; one apical and 2-lateral, near the base.
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Description

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Stems to 3 m. Leaves bright green, coarse textured, 1--2 × dichotomously divided; whorls 1.5--6 cm in diam.; segments linear to filiform, 1.5--2 cm × 1--5 µm, not inflated. Flowers 1--3 mm in diam. Achene dark green to reddish brown, body (excluding spines) 3.5--6 × 2--4 mm, smooth or slightly tuberculate, margins wingless and spineless, facial spines absent; basal spines or tubercles 2, 0.1--12 mm, straight or curved; terminal spine (persistent style) 0.5--14 mm. Fl. and fr. Jun--Sep. 2n = 24, 38, 40, 48.
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Description

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Stems to 3 m; apical leaf whorls densely crowded. Leaves bright green, coarse-textured. Leaf blade simple or forked into 2-4(-5) ultimate segments (forking of largest leaves 1st or 2d order, rarely 3d order), segments not inflated, mature leaf whorls 1.5-6 cm diam., marginal denticles conspicuous, usually strongly raised on broad base of green tissue; 1st leaves of plumule simple. Achene dark green or reddish brown, body (excluding spines) 3.5-6 × 2-4 × 1-2.5 mm, basal spines or tubercles 2 (rarely absent), straight or curved, 0.1-12 mm, spine bases occasionally inconspicuously webbed, marginal spines absent, terminal spine straight, 0.5-14 mm, margins wingless. 2 n = 24, 38, 40, 48.
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Diagnostic Description

Synonym

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Ceratophyllum apiculatum Chamisso
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Ecology

Habitat

Range and Habitat in Illinois

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The native Coontail is occasional to common throughout Illinois. This species is native to a wide area of North America, from where it has spread to other parts of the world. Habitats include quiet inlets of lakes, ponds, rivers with slow-moving currents, marshes, and springs. Generally, Coontail is typically found in bodies of water with muddy bottoms, although it also occurs where the water bottom contains some sand or rocky material. Sometimes Coontail is cultivated as an aquarium plant. It has also been introduced deliberately into polluted bodies of water in bioremediation projects because of its ability to absorb suspended particles of chromium, lead, arsenic, and other chemicals.
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Nile, irrigation canals, shallow or deep water, swamps, lakes, brakish water.

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Fresh to slightly brackish rivers, streams, ditches, lakes, ponds, pools, marshes, swamps; 0-1700m.
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Habitat and Ecology

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Habitat and Ecology

This species typically occurs in nutrient-rich standing or very slow-moving waters. Its apparent capability to tolerate elevated anthropogenic nutrient levels means that it can become very abundant or even dominant to the exclusion of most other species in canals, gravel pits, reservoirs and urban lakes.


Systems
  • Freshwater
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Depth range based on 8 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 2 - 2
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
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Habitat & Distribution

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Streams, ponds, lakes. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jilin, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [Cosmopolitan].
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Associations

Faunal Associations

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The leaves of Coontail provide hiding places for small aquatic organisms and its leaves are sometimes grazed by snails. Both the foliage and seeds of this aquatic plant are eaten by the American Coot (Fulica americana), many species of waterfowl (see the Waterfowl Table), and some turtles (Legler, 1943; Ernst et al., 1994), including the Musk Turtle (Sternotherus odoratus), Snapping Turtle (Chelydra serpentina), Blanding's Turtle (Emys blandingii), Painted Turtle (Chrysemys picta), River Cooter (Pseudemys concinna), and Slider (Trachemys scripta). This aquatic plant is also eaten by carp and, to a lesser extent, by muskrats. The foliage and seeds of Coontail can spread to new wetlands through human activity. For example, when people dump the content of aquariums into waterways that contain Coontail, it can easily establish itself in such habitats. Similarly, because Coontail can cling to anchors, boat trailers, fishing nets, and dredging equipment, it may be transported considerable distances from one body water to another.
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Foodplant / open feeder
adult of Phaedon armoraciae grazes on live, perforated leaf of Ceratophyllum demersum
Remarks: season: 5-11

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Life History and Behavior

Cyclicity

Flowering/Fruiting

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Flowering spring-late fall.
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Flower/Fruit

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Fl. Per.: March June.
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Molecular Biology and Genetics

Molecular Biology

Barcode data: Ceratophyllum demersum

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The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File
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Statistics of barcoding coverage: Ceratophyllum demersum

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Barcode of Life Data Systems (BOLDS) Stats
Public Records: 5
Specimens with Barcodes: 13
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment

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Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2011

Assessor/s
Zhuang, X.

Reviewer/s
Juffe Bignoli, D., Homsombath, K. & Nophasead, L.

Contributor/s

Justification
This species is listed as Least Concern as it is widespread with stable populations and does not face any major threats. It has been very widely introduced and is considered a serious weed.
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National NatureServe Conservation Status

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Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

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NatureServe Conservation Status

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Rounded Global Status Rank: G5 - Secure

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Population

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Population

There is no information on global populations although it is a widespread and common plant in freshwater habitats. It is common in the rivers and lakes in the areas south of Yangtze River in China.


Population Trend
Stable
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Threats

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Major Threats
There are no major threats to this species.
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Management

Conservation Actions

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Conservation Actions
There are no conservation measures in place or needed.
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Relevance to Humans and Ecosystems

Benefits

Cultivation

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The preference is full sun and relatively clear water up to 9' deep that has adequate levels of nutrients; water pH can be mildly acidic to alkaline. At the water's bottom, the soil should consist of mud, sandy mud, or muddy gravel. Coontail is more tolerant of shade than the majority of aquatic plants and it is able to tolerate some turbidity in the water if it is not excessive. This aquatic plant can adapt to sites with either stagnant water or slow-moving currents where there is some protection from wind and waves. Because of its phytotoxic properties, Coontail can inhibit the growth of phytoplankton and blue-green algae (cyanobacteria). At some locations, it can spread aggressively and become a pest.
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Wikipedia

Ceratophyllum demersum

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Ceratophyllum demersum (hornwort, rigid hornwort, coontail, or coon's tail[1]) 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.[1] It is also a popular aquarium plant.

Contents

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 leaves 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 flowers 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.[2][3][4][5][6] 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[citation needed] and a rich nutrient status. It is native to North America, but has spread worldwide as a result of its use as an aquarium and pond plant.[1] In North America, it occurs in the entire US and Canada, except Newfoundland.[7] In Europe, it has been reported as far north as at a latitude of 66 degrees in Norway.[8] Other reported occurrences include China, Siberia (at 66 degrees North), Burkina Faso (Africa), Vietnam, and New Zealand.[9]

Ecology

C. demersum has allelopathic qualities as it excretes substances that inhibit the growth of phytoplankton and cyanobacteria (blue-green algae).[1][10] Its dense growth can outcompete native underwater vegetation, leading to loss of biodiversity. In New Zealand, it has caused problems with hydroelectric power plants.[1]

Cultivation and uses

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 green leaves provide excellent cover for newly-hatched fish. It is propagated by cuttings.[11]

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.

Invasive species

Hornwort is a declared weed under the Tasmanian Weed Management Act 1999 in Tasmania, Australia,[12] and is classed as an unwanted organism in New Zealand.[13]

References

  1. ^ a b c d e Ceratophyllum Demersum on the Global Invasive Species database (2006).
  2. ^ Flora of China: Ceratophyllum demersum
  3. ^ Flora of North America: Ceratophyllum demersum
  4. ^ Flora of NW Europe: Ceratophyllum demersum
  5. ^ Blamey, M. & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. ISBN 0-340-40170-2
  6. ^ Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan ISBN 0-333-47494-5.
  7. ^ USDA PLANTS database on C. demersum as of 2011.
  8. ^ ISSG database, reports in Norway (based on Mjelde, 1997)
  9. ^ ISSG: distribution of C. demersum
  10. ^ http://www.thekrib.com/Plants/Algae/cyanobacteria.html#4
  11. ^ Hiscock, P. (2003). Encyclopedia of Aquarium Plants. Interpret Publishing, United States and Canada ISBN 0-7641-5521-0.
  12. ^ "Hornwort". Department of Primary Industries, Parks, Water and Environment. http://www.dpiw.tas.gov.au/inter,nsf/WebPages/LBUN-87B7WC. Retrieved 21 September 2012.
  13. ^ "Hornwort". MPI Biosecurity New Zealand. 29 May 2012. http://www.biosecurity.govt.nz/pests/hornwort. Retrieved 2012-09-21.
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Specimens of Ceratophyllum demersum with short basal spines or tubercles have been misidentified as C . submersum Linnaeus, a species not known in the New World despite reports to the contrary. Ceratophyllum demersum is the most common species of Ceratophyllum in North America and also the least likely to be found with fruit, its reproduction being primarily asexual. Predominantly low leaf order is, therefore, the most reliable means of identifying this species. 

 Noted for its prolific growth, Ceratophyllum demersum occasionally has attained status as a serious weed.

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The plant is used as a cooling agent for biliosness and scorpion sting. The achenes are eaten by wild ducks (Subramanyam, l.c.). It is also commonly cultivated in aquaria.
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This species is widespread throughout China and expected to be reported from additional provinces.
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Comments: As treated here (following Kartesz, 1994), excludes Ceratophyllum echinaceum, sometimes considered a variety of C. demersum. LEM 27Jun95.

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