Syn.: Trapa quadrispinosa Roxb., Trapa laevis J. Presl
Family: Trapaceae Dumort.
Trapa natans

Trapa natans

Distribution: Western, Central and Southeastern Europe, Southern and Southeastern Asia, Southern Siberia, naturalized in Northern America and Australia, evidently also in Eastern Africa.
Ecology: Grows in still water of lower altitudes. Flowers from July to August.
Description: Annual herb with submerged stem, 50–200 cm long, submerged leaves pinnately divided, rosette leaves floating on water surface with rhomboid blades. Solitary flowers with 4 white petals. Very variable species.
Threat and protection: The Water Chestnut is a protected plant in some countries (e.g. Czechia, Slovakia, Poland, Hungary, Germany, Switzerland, Ukraine, Russia).
Trapa natansTrapa natans
Trapa natans
These images were taken in Czechia, Poodří, pond Bezruč (by Ladislav Kovář, 4. 9. 2004) and East Bohemia, pond Farář (by Naděžda Gutzerová, 12. 8. 2009).

Distribution of species in the Czech Republic:
Trapa natans