Herbs or subshrubs, twining, prostrate or rarely erect. Leaves opposite, ovate, oblong or ovate-lanceolate. Flowers in sessile or pedunculate, umbelloid or lax dichasial cyme. Calyx 5-partite, lobes triangular, ovate or lanceolate, acute. Corolla rotate, deeply 5-lobed, lobes ovate, slightly overlapping to the right. Corona single, of 5 erect, fleshy, triangular segments, adnate to the short staminal-column. Anthers small, with membranous appendages. Pollinium solitary in each loculus, ascending or caudicle ascending and pollinium pendulous without a pellucid margin. Stigma disciform, 5-angled. Follicles fusiform, acuminate, smooth. Seeds comose.