Perennial or annual usually stemless herbs. Leaves generally radical, tufted or spreading, simple, flat, nerved. Flowers regular,., hermaphrodite or rarely unisexual, often dimorphic, generally in spikes terminating naked axillary scapes. Calyx inferior, persistent, deeply 4-partite, imbricate. Corolla gamopetalous, hypogynous, scarious; tube cylindric; limb with 4 spreading lobes with incurved margins. Stamens 4, rarely fewer, inserted on the tube of the corolla and alternate with its lobes; filaments usually long, capillary, exserted; anthers large, versatile. Ovary superior, 2–4-celled; style filiform, with two lines of stigmatic papillæ; ovules few or many affixed to the septum, or solitary and basal in each cell. Fruit a 1–4-celled capsule with transverse dehiscence. Seeds usually peltate; albumen fleshy; embryo cylindric, radicle inferior.

A small and very distinct order, widely spread over the globe, but most abundant in temperate regions. Genera 3; species variously estimated, from 60 to over 200. The properties of the order are unimportant, and the species are mostly of unattractive appearance.