(Trapa natans bicornis)
Trapa natans is an annual aquatic plant with a submerged flexuous stem that anchors into the mud and extends upward to the surface of the water. It features a rosette of floating, fan-shaped leaves, each leaf having a slightly inflated petiole (stem); the roots are fine, long and profuse. The small, 4-petalled flower is white and the fruit is a large nut with four sharp spines.