Pubescent or glabrous, unarmed herbs or shrubs. Leaves opposite or whorled; blades entire or sometimes crenate. Flowers showy, yellow or red, mostly long peduncled, borne in subterminal spikes; bracts 4-ranked, large, ovate-lanceolate, imbricate; bracteoles linear-lanceolate, shorter than calyx, pubescent. Calyx deeply 5-parted, lobes unequal; corolla tube narrow, longer than limb, incurved, limb deeply divided to throat, forming a 5-lobed lip, lobes unequal, imbricate; stamens 4, included, anthers longer than filaments, with one fertile theca, sterile theca bearded throughout, muticous, connective mucronate; ovary with 2 ovules in each locule, style thickened upwards, stigma minutely bifid. Capsules oblong, flattened, quadrangular, 4-seeded, retinacula present, septae with attached retinacula remaining attached to inner wall of mature capsule; seeds ellipsoid-ovate, beset with fringed scales or trichomes.
Africa cultivated, Arabia present, Indo-Pakistan subcontinent present, Madagascar present, Malaysia cultivated, gardens in Neotropical regions cultivated, tropical Africa present
A genus of about 50 species, distributed mainly in Tropical Africa, Madagascar, Arabia, and the Indo-Pakistan subcontinent; 1 species is commonly cultivated in gardens in Neotropical regions as well as in Malaysia and Africa.