The waterwheel plant is a free-floating aquatic plant. It is carnivorous and traps its prey with the help of clam-like  lobes present on the tip of each whorl of the leaf. The loblis Ira lined with trigger hairs. When small aquatic invertebrates floating In the water come Into contact with these hairs, the lobes snap shut. This process of trapping the  prey takes less than half  a second, one of the fastest examples of plant movement ever recorded. The waterwheel plant is So called because its leaves are arranged in 5-9 wheels around the stem. The floating stems of the plant reach a length  of  6-10  cm and air sacks in the petioles of the leaves help it to float rapidly.