An aquatic herb, either floating or submerged. The stem is hollow, smooth and elongate. Leaves are highly variable. The submerged leaves are flattened and dissected into many segments 1-2 mm. The emergent leaves, if present, are 3-parted.
Flowers are on emergent, long, thick stalks.
Nutlets are 1.7-2.2 mm. The nutlets have a corky margin at maturity. In flower from April to June.