A herb which keeps growing from year to year. It lies along the ground. It forms roots where the nodes are in contact with soil or water. It grows up to 1 m tall. The stems are hollow. They are 3 cm across. There can be leaves under the water but most are above and divided. They are 20 cm long with 2-12 pairs of leaflets without stalks. The lowest pair of leaflets are 5 cm long by 3 cm wide and each pair along the leaf get shorter. The end leaflet has several lobes. The flowers are in compound groups on equal length stalks. The petals are white.