Water chestnut

The water chestnut Trapa natans is a floating aquatic plant, growing in slow-moving water up to 5 meters deep. It is native to warm temperate Eurasia and Africa.

The species has two types of leaves, submerged and floating. The floating leaves are ovoid, 2–3 cm long, on petioles 5–9 cm long; the submerged leaves are finely divided.

It was introduced to North America around 1874, and escaped cultivation in the eastern United States, where it has become an invasive species from Vermont to Virginia.

The unrelated Chinese water chestnut Eleocharis dulcis is a sedge whose tuberous roots are used in Chinese cooking.