Annual or perennial, succulent herbs or subshrubs; nodes glabrous or pilose. Leaves alternate, opposite or in a basal rosette, simple, often succulent, sessile or petiolate; stipules scarious, lacerate or fimbriate, or modified into hairs. Inflorescence a terminal or lateral raceme, cyme or panicle, or the flowers solitary and axillary. Flowers bisexual, regular; sepals 2(4-8), free or united below, imbricate, persistent or caducous, scarious or herbaceous; petals (2-)5(-12), free or united below, imbricate, deciduous; stamens 4-5 or more, free or adnate at base to corolla, filaments filiform, anthers 2-locular, basifixed, longitudinally dehiscent, introrse; ovary superior, half-inferior or inferior, 2- to 5-carpellate and 1-locular, placentation free-central or basal, ovules several to numerous, campylotropous, often on long funicles, styles and stigmas 1-9, free or united below. Fruit a loculicidal or circumscissile capsule (rarely an indehiscent nut); seeds (1-2 by abortion) 3-numerous, compressed, lenticular, reniform or cochleate, sometimes strophiolate, often tuberculate, embryo curved, perisperm often present and abundant, endosperm rudimentary, mealy.