Azolla pinnata

Azolla pinnata is a species of fern known by several common names, including feathered mosquitofern and water velvet. It is native to much of Africa, Asia from China to Japan, India and the Philippines, and parts of Australia. It is an aquatic plant, its frond floating upon the surface of the water. It grows in quiet and slow-moving water bodies, because swift currents and waves break up the plant.