Herbs, mostly rigid, erect or climbing. Stem and branches diffuse, quadrangular. Leaves (2-) 4-10 in a whorl, cordate, lanceolate or obovate, rarely linear. Inflorescence of axillary and terminal cymes or panicles. Flowers small. Calyx-tube ovoid or globose, enclosing the ovary and adherent to it, lobes obsolete. Corolla subcampanulate or rotate; lobes 5, valvate. Stamens 5, included in the corolla-tube, rarely 4 or 6, filaments very short, anthers somewhat exserted. Disc annular. Ovary bilocular or 1-locator by abortion; styles 2 or bifid; stigma capitate; ovules solitary in each locule, attached near the base of septum. Fruit a berry, didymous or globose by suppression of one carpel, fleshy; seeds suberect, adhering to the pericarp, testa membranous.