Vines, perennial, semiwoody. Leaves alternate. Inflorescences terminal or axillary panicles, mostly 50-100-flowered. Flowers epigynous (hypogynous in all other genera); sepals 4(-5); stamens 15-20; carpels (3-)4, connate at least halfway proximally; ovary inferior (3-)4-locular, eventually 1-locular by abortion of septa; style 1; stigmas (3-)4. Fruits cypselas, turbinate, crowned by winglike sepals. Seed 1, by abortion of other (2-)3 ovules.