Terrestrial, caulescent, decumbent to erect herbs, with scaly rhizomes. Stems seldom branched. Leaves opposite, subequal to equal in a pair, venation pinnate, foliar nectaries absent. Flowers axillary, 1 to several in fascicles; epedunculate; bracteoles absent (in Guianan species); pedicellate. Calyx lobes nearly free; corolla white, blue, lavender, purple, rose-pink, scarlet to orange or yellow, often with darker spots, tubular, cylindric to campanulate; stamens included, filaments not connate, anthers coherent by their apices, dehiscing by longitudinal slits, thecae parallel or divergent at base; staminode present; disc absent, or when present, annular, entire or 5-lobed; ovary inferior, stigma stomatomorphic or 2-lobed. Fruit a dry, brown capsule, loculicidally dehiscent, 2-valved, valves opening slightly.
Argentina: present Guianas: present Southern America:, Bolivia (Bolivia ‒ present); Panamá (Panamá ‒ present) Trinidad: present rainforests of C and S America: present
About 10 species distributed in the rainforests of C and S America, from Panama to Bolivia and Argentina, and to the Guianas and Trinidad; 2 species in the Guianas.