Woody lianas or lianoid shrubs. Leaves opposite, entire, eglandular; stipule absent or small and deciduous. Inflorescences paniculate, rarely a raceme or cyme, axillary or terminal; peduncles articulated distally; pedicels usually bracteolate. Flowers 5-merous, bisexual, actinomorphic. Sepals 5, sometimes connate at base, eglandular. Petals 5, yellow or white, not clawed, entire, explanate or recurved. Stamens 10; filaments filiform, free or sometimes connate at base; anthers basifixed. Ovary 3-lobed, lobes abaxially flattened, margins ± winged; styles 3, free; stigma capitate. Samaras 3, often attached by a carpophore, each 3-winged; lateral wings connate forming 1 large wing, orbicular to oblong, membranous or leathery, palmately veined, sometimes shortly crested at middle; abaxial wing well developed or absent. Seeds cylindric, located at center of samara.

About 20 species: tropical Asia; nine species (five endemic) in China.