Description from Flora of China
Pachynocarpus J. D. Hooker; Retinodendron Korthals (1840), not Zenker (1833) [Fossil]; Sunaptea Griffith.
Trees of main canopy and understory, unbuttressed, white resinous. Bark gray, smooth, often with annular striations. Stipules caducous, small; leaf blade ± leathery, pinnately veined, tertiary reticulate veins conspicuous, margin entire. Flowers in axillary or terminal cymose panicles, usually stellate pubescent. Calyx tube short; sepals narrowly imbricate, equal or subequal. Petals white, often with a mauve suffusion, lorate, large, falling separately. Stamens 15; filaments unequal, stout; anthers ellipsoid; connective appendages short, obtuse. Ovary ovoid, pubescent; style cylindric, short; stigma capitate or conic, prominent, entire or dentate. Nut globose or ellipsoid, 1- or 2-seeded; calyx segments equal or unequal, with 2 developed into long wings.
Vatica cordata Hu is a synonym of Tridynamia sinensis (Hemsley) Staples var. sinensis in the Convolvulaceae (see Fl. China 16: 282. 1995).
About 65 species: Cambodia, China, E and S India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Sri Lanka, Thailand, Vietnam; three species (one endemic) in China.