Terrestrial, caulescent, decumbent herbs, without modified stems. Stems unbranched. Leaves opposite, equal or subequal in a pair, venation pinnate, stomata usually in groups, foliar nectaries absent. Flowers axillary, 1 to many in pedunculate, subumbellate to racemose-paniculate cymes; bracteoles small, persistent, leaf-like; pedicellate. Calyx lobes connate at base up to half their length; corolla white to blue, pink, or lilac, rotate or campanulate, sometimes ventricose; stamens exserted or included, filaments not connate, anthers free, dehiscing by longitudinal slits, thecae divergent; staminode present (when fertile stamens 4); disc absent; ovary superior, stigma slightly 2-lobed. Fruit a dry, loculicidally and septicidally dehiscent, light brown capsule, 4-valved, valves opening slightly.
C and S America present, Guianas present present, Southern America: Bolivia (Bolivia present); Guatemala (Guatemala present), southeastern Brazil present
About 16 species in C and S America from Guatemala southwards to Bolivia, east to the Guianas, and also in southeastern Brazil; 4 species in the Guianas.