Annual herbs, sometimes with thick erect stems. Lvs alternate, simple, entire or denticulate. Fls in spikes, racemes, or sometimes solitary in the upper lf axils, actinomorphic. Buds erect to pendulous. Floral tube obconic, campanulate or funnelform, short or long and slender, usually with ring of hairs within. Sepals 4, often coloured, reflexing at anthesis. Petals 4, sometimes clawed, often lobed, white, cream, pink to crimson, mauve or purple. Stamens 8 or 4; anthers erect and basifixed. Stigma 4-lobed. Capsule 4-celled, cylindric to clavate, terete to quadrangular; beak present or 0. Seeds numerous, brown or grey, scaly or minutely tuberculate.