Trapa natans 

Scope: Global
Language: English

Translate page into:

Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Myrtales Trapaceae

Scientific Name: Trapa natans
Species Authority: L.
Regional Assessments:
Common Name(s):
English Water Caltrop, Water Chestnut
French Châtaigne d'Eau, Mâcre, Mâcre nageante
Trapa astrachanica (Flerow) N.A.Winter
Trapa carinthiaca (Beck) V.N.Vassil.
Trapa colchica Albov
Trapa conocarpa (F.Aresch.) Flerow
Trapa cruciata (Glück) V.N.Vassil.
Trapa europaea Flerow
Trapa hungarica Opiz
Trapa maeotica Woronow
Trapa muzzanensis (Jäggi) Szafer
Trapa rossica V.N.Vassil.
Trapa septentrionalis V.N.Vassil.
Trapa spryginii V.N.Vassil.
Taxonomic Notes: The taxonomy of the genus Trapa appears to be complex. The distribution of T. natans sensu stricto is obscured by variation in the degree to which other taxa are recognised. It is likely that the information employed here will include information on other taxa and will therefore present a more positive idea of the status of the species than is actually the case.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2010-03-25
Assessor(s): Gupta, A.K.
Reviewer(s): Zhuang, X., Bounphanmy, S., Homsombath, K. & Juffe Bignoli, D.
Contributor(s): Allen, D.J.
This floating aquatic plant is found most of Europe and Asia, and into China, and is considered an introduced invasive plant elsewhere. The species is widespread and although is declining in Europe, it is not thought to be in risk of extinction at a global level. It is therefore assessed as Least Concern.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The species has a wide distribution through Eurasia and Asia. It has been reported from most of Europe, into southern Sweden and into European Russia. It occurs throughout most of Asia, into China, the Philippines and Malaysia. It has apparently been introduced into Australia and North America, where it is now widespread and may be invasive (Arber 1920, Cuong et al. 1973, Crow and Hellquist 2000, Tzvelev 2005, Chen et al. 2005, USDA 2010).
Countries occurrence:
Afghanistan; Albania; Algeria; Angola (Angola); Austria; Bangladesh; Belarus; Botswana; Bulgaria; China (Anhui, Fujian, Gansu, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jilin, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Xinjiang, Yunnan, Zhejiang); Croatia; Czech Republic; France (France (mainland)); Germany; Greece (Greece (mainland)); Guinea-Bissau; Hong Kong; Hungary; India; Indonesia; Italy (Italy (mainland)); Japan; Kazakhstan; Kyrgyzstan; Lao People's Democratic Republic; Latvia; Liechtenstein; Malawi; Malaysia; Moldova; Mongolia; Montenegro; Mozambique; Myanmar (Myanmar (mainland)); Namibia; Nepal; Pakistan; Philippines; Poland; Romania; Russian Federation (Central European Russia, East European Russia, North European Russia, Northwest European Russia, South European Russia); Serbia (Kosovo, Serbia, Serbia); Slovakia; Slovenia; South Africa; South Sudan; Spain (Baleares, Spain (mainland) - Regionally Extinct); Sudan; Sweden; Switzerland; Taiwan, Province of China; Tajikistan; Tanzania, United Republic of; Thailand; Tunisia; Turkey (Turkey-in-Europe); Uganda; Ukraine (Krym, Ukraine (main part)); Uzbekistan; Viet Nam
Regionally extinct:
Australia; United States
Additional data:
Upper elevation limit (metres):150
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The species is not very common in the wild across the Asian part of its range and it is very rare in Europe.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This plant is an annual (up to 3 m height) floating-leaved plant, growing in stagnant waters, lakes, channels with weak currents, ponds and marshes. It primarily occurs in unpolluted nutrient-rich lowlands, but not in strongly calcareous waters that have a muddy bottom and plenty of light; it is important as food source for birds and provides fish spawning grounds.


Use and Trade [top]

Use and Trade: The fruits are important in continental Asia, Malaysia and India, especially in China. Several countries in southeast Asia, and also Chinese communities in Europe and North America, import the fruit directly from China. It is widely cultivated across the region. Fruits are used in the preparation of liniments to treat elephantiasis, pestilent fevers, rheumatism, sores, sunburn and skin complaints. Used also as food for pigs and other livestock in southeast Asia.

In India, the kernel of the plant is used as laxative and is a good source of nutritious flour. The unripe kernels are also used as vegetable or eaten raw. The flour from the dried kernel provides a good source of income for people across India and Nepal.

Threats [top]

Major Threat(s): In Europe the species is declining, however the causes of the decline are not clear, although they are usually attributed to loss and degradation of habitats. In Asia there are no major threats to the species, though wetland loss and degradation are likely to become significant there too.

Conservation Actions [top]

Conservation Actions: Included in some regional and national red lists in Europe but no conservation actions required globally.

Citation: Gupta, A.K. 2011. Trapa natans. The IUCN Red List of Threatened Species 2011: e.T164153A5752771. . Downloaded on 23 April 2017.
Disclaimer: To make use of this information, please check the <Terms of Use>.
Feedback: If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided