An erect glandular pubescent or puberulous, annual herb, about 1 m high, branching from the base: stems obscurely 4 angled; leaves opposite, lower leaves lobed or often pedatisect, upper leaves narrowly oblong, subentire, glabrous above, puberulous beneath; flowers axillary, solitary or 2, rarely fascicled, shortly pedicelled; two yellow glands at the base of pedicels, with a strong, unpleasent odour; calyx lobes 5, small, lanceolate; corolla white or pink, tubular, denesely hairy, 4-5 cm long, tube 2 cm long, inflated above the base, lobes 5, rounded, lower lip longer and reflexed with deep rosy markings, lobes pubescent outside; stamens 4, didynamous, anthers free, sagitate, cells subparallel; disk annular; ovary hispid, 2-celled, becoming 4-locular by radial false septum; ovules many in each locule; stigma 2-lamellate; capsules 1.5-3 cm long, tetragonous, deeply 4-grooved; seeds white, brown or black, smooth wingless.