The water chestnut is a floating annual aquatic plants, growing in slow-moving water up to 5 meters deep, native to warm temperate parts of Eurasia and Africa. They bear ornately shaped fruits that resemble the head of a bull, each containing a single very large starchy seed. The fruits are about 4 cm in diameter are used as food; they have a white heart-shaped core inside. When extracted from the shell, they are eaten raw, boiled, roosted, fried, or dressed in various ways after being reduced to flour. Fruit or nut or seed contains manganese and starch. The nutritive value of the kernel is found to equivalent to that of rice. It has been cultivated in China for at least 3,000 years for these seeds, which are boiled and sold as an occasional street side snack in the south of that country.