Woody vines. Leaf blade not peltate, palmately veined. Inflorescences axillary, paniculate. Male flowers: sepals 6 in 2 whorls, imbricate in bud, extending outward when blooming, outer whorl narrower; petals 6, with basal margins inflexed and clasping opposite stamen; stamens 9, rarely 12, free, anther large, squared globose, dehiscing nearly apically. Female flowers: sepals and petals as in male flowers; staminodes 9; carpels 3, saccate-semiovate, style curved outward, stigma expanded and lobed. Drupes oblate, slightly oblique, style scar near base; endocarp rather flattened, with both sides concave and smooth, abaxially with 2 rows of spines projecting along midrib, ornamented with branching ridges in a row on both surfaces; condyle lamella-shaped. Seed half-moon-shaped; endosperm rich; cotyledons shorter than radicle.

One species: China, N India, Japan, Nepal, N Thailand.