The water caltrop, water chestnut, buffalo nut, bat nut, devil pod, ling nut, singhara,pani-phal is any of three extant species of the genus Trapa: Trapa natans, T. bicornis and the endangered Trapa rossica. The species are 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, which in the case of T. bicornis resemble the head of a bull or the silhouette of a flying bat. Each fruit contains a single very large starchy seed. T. natans and T. bicornis have been cultivated in China and India for at least 3,000 years for the edible seeds.