This plant is a marsh herb that trails along the ground and floats on water, with roots forming at the nodes. Its leaves are arranged opposite to each other and vary in shape from elliptic to linear or oblong, with obtuse to subacute tips and dentate margins. The base of the leaves narrows down, and both leaf surfaces are smooth (glabrous). The plant produces sessile capitulum inflorescences, which occur both in the axils of leaves and at the tips of stems.