Annual herbs, sometimes suffruticose, glabrous; branches often prostrate and spreading. Basal leaves crowded into a rosette, cauline leaves opposite or whorled; blade linear to spathulate, sometimes slightly fleshy; stipules small, scarious and caducous, or absent. Inflorescences of axillary fascicles, or solitary flowers; flowers pedicellate. Sepals 5, imbricate in bud, not apically appendaged; petals absent; stamens 3-10, usually 5, filaments filiform or widened, united at base; ovary 3- to 5-locular, ovules numerous, styles and stigmas as many as locules. Capsule loculicidal, membranous, after dehiscence with a central column bearing persistent funicles; seeds few to numerous, trigonous or more or less reniform, shiny, small, estrophiolate, testa granular or sculptured.