The waterwheel plant (Aldrovanda vesiculosa) is closely related to the Venus flytrap. In fact, it is basically just a small, aquatic version of its famous big brother. They are entirely aquatic and float freely, without roots just below the surface of the water. Whorls of tiny snap-traps string together to form little plants 3-4" long. The traps snap shut on all kinds of aquatic creatures, but they are prone to catching mosquito larvae by the head. They are extremely endangered in the wild. They're native to the old world; Europe, Africa, Asia, and Australia.
They can be challenging to cultivate. We grow ours successfully in a large plastic basin. In the bottom of the tub we put about 3" of 1 part peat moss to 1 part clay. Another inch of sand or aquarium gravel should be put over that to hold everything down. We advise planting aquatic monocots like rushes in the bottom; they will release carbon dioxide, which helps the Aldrovanda. A healthy population of mosquito larvae or water daphnia is important as they need a steady supply of prey. They require a lot of sun, but beware of algae that may crowd out the Aldrovanda. Oak leaves or pine needles are good to add to the water periodically. In the fall the plants form dormant buds called turions that sink to the bottom where they over winter. In the spring they float back to the top and emerge.
We are currently working on production of these wonderful plants but we do not have any ready to ship at this time. If you would like to be added to our waiting list please email us. But, please be aware that we do not expect to have them available until late spring or early summer.