Annual or biennial, glabrous herbs. Leaves sessile, sometimes rosetted at base. Inflorescence a dichasium or monochasium. Calyx narrowly (4–)5-lobed for at least half its length; corolla-lobes (4–)5, spreading above a narrow tube; stamens shortly exceeding corolla-tube, partly adnate to tube near base, anthers strongly twisted after dehiscence; ovary cylindric, 1-locular (but often appearing 2-locular due to thickened septa), style slightly bifid, stigma lobes reniform to shoe-shaped, fleshy. Capsule linear, septicidal, initially opening terminally, remaining enveloped in withered corolla; seeds numerous, small, reticulate.
About 20 species from Eurasia; 4 species in Australia, all of which are naturalised.