Annual to perennial herbs, glabrous, papillose or hairy. Leaves simple to pinnate. Inflorescence a raceme. Sepals suberect, inner pair saccate; petals clawed, yellow or white; stamens 4 or 6. Fruit usually elongate (mostly more than 3 times as long as broad), often curved, dehiscent; style usually persistent, up to 4 mm long, bilobed to capitate; valves convex, without visible veins or with weak midvein fading below apex; seeds in 1–2 rows per locule.
About 85 species, cosmopolitan; 8 species in Australia, 2 of them introduced.
A variable genus, with fruits ranging from ellipsoid to linear, but always with valves convex and with indistinct venation. See note under Nasturtium.