The water caltrop, water chestnut, buffalo nut, bat nut, devil pod, ling nut, lin kok, singhara (Hindi: सिंघाड़ा), (Urdu: سنگھاڑا‎),pani-phal (Hindi: पानीफल) 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.