A long-lived herbaceous plant growing 30-150 cm tall. It produces numerous creeping underground stems that send up short-lived upright shoots. Its paired or alternately arranged leaves are deeply lobed. Separate male and female flower-heads are produced on different parts of the same plant. The drooping greenish-yellow male flower-heads (2-4 mm across) are borne in upright elongated clusters. The stalkless female flower-heads are borne in the forks of the uppermost leaves.