Annual or perennial herbs or undershrubs. Leaves often partly in (pseudo) whorls at the base of the inflorescence, short-petioled or sessile, the bases connected by interpetiolar stipules or sheaths. Inflorescences terminal and/or in the upper leaf-axils, cincinnous, sometimes reduced to a few flowers. Flowers sessile or almost so, 5-merous. Calyx: sepals free or connate at the base, inside at the base with some colleters. Corolla: tube tubular, lobes valvate in bud, shorter than the tube. Stamens included, anthers dorsifixed, introrse, lanceolate or ovate, 2-celled. Ovary superior, 2-celled, with many ovules. Capsule 2-lobed, 2-celled, 4-valved, valves caducous with the exception of a cupular basal part (Fig. 38e). Seeds some per cell, globose to angular, verrucose; endosperm fleshy or cartilaginous.
Fls 5-merous; cal-lobes valvate; cor tubular or salverform, its 5 short lobes valvate in bud; stamens inserted below the middle of the cor-tube, the linear anthers somewhat exsert; ovary bilocular, the style eventually long-exsert; stigma l; capsule strongly didynamous, each half subglobose, loculicidal; seeds angularly subglobose; herbs with fls in terminal secund cymes. 50, warmer parts of the New World.