An annual underwater plant. It has runners or stolons. The leaves are like ribbons. They narrow at the end and have an easy to see midrib and veins which run along the leaf. Leaves are 2.5-60 cm long and 0.2-1.2 cm wide. The bract around the flowers is 2-12 cm long and forms a cylinder. There is one or two flowers like stalks. They form tubes. The fruit is 2-8 cm long and 0.5 cm wide. There are many seeds inside. These are 1-2 mm long.