Ceratophyllum demersum 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Ceratophyllales Ceratophyllaceae

Scientific Name: Ceratophyllum demersum L.
Regional Assessments:
Common Name(s):
English Rigid Hornwort, Coontail, Hornwort
French Ceratophylle émergé, Cornifle Nageant, Cornille, Herbe à cornes
Taxonomic Notes:

Ceratophyllum is a complicated genus with a range of taxa named but inconsistently recognized. Cook (1970) states that the genus includes four polymorphic species, but in parts of Europe some of the morphological variants are recognised as species or at a subordinate level. Whilst at least in the west, C. demersum s.s. is so widespread and abundant that it is unlikely that taxonomic issues will affect its conservation or Red List assessment, inconsistent recording within the C. demersum complex is likely to affect the Red List assessments of any subordinate taxa assessed.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2017
Date Assessed: 2016-05-13
Assessor(s): Lansdown, R.V. & Beentje, H.J.
Reviewer(s): Luke, W.R.Q.
Contributor(s): Zhuang, X., Patzelt, A. & Knees, S.
Facilitator/Compiler(s): Maiz-Tome, L.
The species is globally widespread and is not subject to any known significant threat. Ceratophyllum demersum is therefore assessed as Least Concern.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species has a more or less cosmopolitan distribution. It 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), and is widespread throughout China (Flora of China; eFlora 2011). It occurs in Africa north and south of the Sahara including Madagascar, as well as Australasia and North, Central and South America. The species has apparently been introduced to Mauritius, New Zealand and Hawaii (World Checklist of Selected Plant Families 2010).
Countries occurrence:
Albania; Andorra; Angola (Angola); Argentina; Australia (Coral Sea Is. Territory, Queensland); Austria; Belarus; Belgium; Benin; Bosnia and Herzegovina; Botswana; Brazil; Bulgaria; Burkina Faso; Burundi; Cambodia; Cameroon; Canada (British Columbia, Ontario, Québec); Central African Republic; Chad; Chile; China (Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hunan, Jiangsu, Jilin, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Tibet [or Xizang], Xinjiang, Yunnan, Zhejiang); Congo; Congo, The Democratic Republic of the; Costa Rica (Costa Rica (mainland)); Côte d'Ivoire; Croatia; Cuba; Czech Republic; Denmark; Djibouti; Dominica; Egypt (Egypt (African part)); Eritrea; Estonia; Ethiopia; Fiji; Finland; France (Corsica, France (mainland)); Gabon; Germany; Ghana; Greece (Greece (mainland), Kriti); Grenada; Guernsey; Guinea-Bissau; Honduras; Hungary; India; Indonesia (Jawa, Kalimantan, Lesser Sunda Is., Maluku, Sulawesi, Sumatera); Iran, Islamic Republic of; Iraq; Ireland; Italy (Italy (mainland), Sardegna, Sicilia); Jamaica; Japan; Kenya; Lao People's Democratic Republic; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Madagascar; Malawi; Malaysia (Sabah, Sarawak); Martinique; Mauritania; Moldova; Montenegro; Morocco; Mozambique; Namibia (Caprivi Strip); Netherlands; Nicaragua (Nicaragua (mainland)); Nigeria; Norway; Oman; Panama; Papua New Guinea (North Solomons, Papua New Guinea (main island group)); Philippines; Poland; Portugal (Azores, Portugal (mainland)); Puerto Rico (Puerto Rico (main island)); Romania; Russian Federation (Central Asian Russia, Central European Russia, East European Russia, European Russia, Kaliningrad, Khabarovsk, Magadan, North European Russia, Northwest European Russia, Sakhalin, South European Russia, Tuva, Yakutiya); Rwanda; Saint Lucia; Saint Vincent and the Grenadines; Saudi Arabia; Senegal; Serbia; Slovakia; Slovenia; South Africa (KwaZulu-Natal); South Sudan; Spain (Baleares, Spain (mainland)); Sudan; Sweden; Switzerland; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Togo; Trinidad and Tobago; Turkey (Turkey-in-Europe); Uganda; Ukraine (Ukraine (main part)); United Kingdom (Great Britain, Northern Ireland); United States (Alaska, Arizona, California, Colorado, Connecticut, Hawaiian Is. - Introduced, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Texas, Utah, Vermont, Washington, West Virginia, Wisconsin, Wyoming); Venezuela, Bolivarian Republic of; Viet Nam; Yemen (North Yemen, South Yemen)
Mauritius (Mauritius (main island) - Native); New Zealand (North Is.)
Additional data:
Upper elevation limit (metres):2000
Range Map:Click here to open the map viewer and explore range.

Population [top]


This is a widespread and common plant in many freshwater habitats. It can be common or locally dominant, and can form thick mats just below the water surface.

Current Population Trend:Stable
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:

This species grows in static and slow-moving shallow or deep water in lakes, ponds, rivers and streams, and also in reed swamps. It can tolerate brackish conditions in estuaries and forms thick mats just below the surface.

Continuing decline in area, extent and/or quality of habitat:No

Use and Trade [top]

Use and Trade:

This species is used as a floating freshwater plant in both cold water and tropical aquaria.

Threats [top]

Major Threat(s):

There are no known significant past, ongoing or future threats to this species.

Conservation Actions [top]

Conservation Actions: No conservation actions are currently known or likely to be needed.

Citation: Lansdown, R.V. & Beentje, H.J. 2017. Ceratophyllum demersum. The IUCN Red List of Threatened Species 2017: e.T164459A84277517. . Downloaded on 16 October 2018.
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