Tufted annual or stoloniferous perennial herbs, terrestrial or aquatic, sometimes the basal internodes becoming tuberous. Leaves opposite or alternate, sessile or indistinctly petiolate. Inflorescence cymose, few-flowered, sometimes reduced to 1 flower; bracts 1–several; sepals free or shortly united at base, persistent; petals 5, united into a short tube that may be cleft to the base on one side after anthesis; stamens 3 or 5; style trifid; ovary superior, ovules 3. Capsule splitting longitudinally into 3 valves; seeds 3 (or fewer by abortion).
About 19 species from North America, extending to the Southern Hemisphere including New Zealand and Australia; 2 species in Australia (1 naturalised).
Species previously segregated into Neopaxia Ö. Nilsson have been placed back in Montia. Phylogenetic studies of Montieae have shown Neopaxia to be nested within Montia (Heenan 2007; O’quinn & Hufford 2005).