Ovary superior, deeply 4-lobed. Calyx 2-4 mm long. Calyx 3-6 mm long. Nutlets ovoid, attached at the base, contain 1 seed but do not open. Typically grows on moist soils of open sites, waste places, fields, ditches, abandoned gardens.
Plants thrive on fertile garden soils.
Tolerates cold winter climates. Expected to expand range. Above ground parts die back in cold winter climates. Seed germinates rapidly, especially on wet, peaty or loam soils, and in water. Although fragmented roots can generate new plants, repeated cultivation can eliminate weedy populations, especially when timed to prevent seed production.