Trapa natans Linnaeus, 1753

Trapa natans imageSynonyms: Trapa longicarpa Jank., 1961

Common names: Bulg: Voden orekh, Julyun; Russ: Vodyanoy orekh plavayushchiy; Ukr: Vodyany gorikh plavayuchy



Taxonomic descriptions: Annual water herb. Submarine stem is 40-150 cm length. Leaves 3-4 cm length, 3-4.5 cm width, floating, wide diamond-shaped, from below with hairs along veins. Petioles are 3-10 cm length, cylindrical or with oblong swellings near leaf blades. Fruits (diameter 6-10 mm) with firm cover, four-corned.

Trapa natans arealIUCN Status:
    World level: VU
    Black Sea Regional level: VU
    Subregion level: VU


Habitats type, Critical habitats, Limiting factors: Geographic area of species covers both Europe and Mediterranean. The species grows in stagnant or slightly flowing waters 50-250 cm mostly in river valleys, in silt soils. Occurs in pure growth or with other water plants.

Biology: Probably, the species has obligate self-fertilization: there is no data about cross fertilization. Fruits are distributed by flowing waters, mammals and birds. Seeds have a good germination power (up to 40-50 years), annually only a part of them shoot. Flowering during VI-VII. Fruit-bearing - VIII-IX. Reproduction only by seeds.

Population trends: Populations are numerous, particularly in the “Dunajskiye plavni” reserve (Ukraine).

Threats: Drying of wetlands, chemical pollution, output for animal feeding.

Conservation measures taken: The species has been entered in the Red Data Books of Ukraine (1996) and Bulgaria (1984), protected in the Danube delta (Ukraine and Romania).

Conservation measures proposed: To create new protected zones.


  1. Lucas, G. 1977. List of rare, threatened and endemic plants in Europe. Strasbourg. 286 p.
  2. Peev, D. 1979. Flora na NRB. VII. Sem. Trapaceae, pp.444-446.
  3. Rare and vanishing plants of the USSR/Ed. by Ac. A. Takhtajan. - Leningrad, 1981. - 264 p.
  4. Red Data Book of Russian Soviet Federal Socialist Republic. Plants. - Moscow, 1988. - 590 p.
  5. Red Data Book of Bulgaria. Vol. 1. Plants. - Sofia, 1984. - 447 p.
  6. Red Data Book of Ukraine. Vegetable Kingdom. - Kyiv, 1996. - 606 p.
  7. Tchopik V.I. Rare and vanishing plants of Ukraine. - Kiev, 1978. - 216 p.
  8. Zaverucha B.V., Andrienko T.L., Protopopova V.V. Protected plants of Ukraine.- Kiev, 1983.176 p.

Compiled by: S.Dyatlov, M. Filipova, T.Vasilieva