Mostly trailing, prostrate or twining herbs or undershrubs, annual or perennial. Leaves petiolate, petiole often provided with a nectiferous gland at the base; base cordate, hastate or sagittate, ochrea usually truncate, deciduous. Flowers in loose axillary fascicles, terminal racemes or panicle; bracts short, tubular. Perianth 5 (-6)-parted, usually accrescent in fruit, in 2 whorls the outer tepals keeled or membranous or winged on the back, increasing in size in fruit. Stamens 8, shorter than perianth, filaments dorsiventrally flattened or cylindical and dilated at the base. Ovary trigonous, eglandular, styles short, stigmas capitate or fringed. Nut trigonous, smooth or slightly granulate, included in the perianth.