Description from Flora of China
Trees, rarely shrubs, dioecious, rarely monoecious or polygamous. Leaves alternate; stipules small, usually early caducous; petiole usually present, often thickened at apex; leaf blade leathery, pinnate-veined, margin entire or toothed. Flowers hypogynous, in axillary, ± branched cymes, these sometimes very short or reduced to fascicles or to a solitary flower, or rarely flowers in long racemelike panicles from trunk or older branches; bracts small to minute, sometimes persistent; pedicels articulate. Sepals (3 or)4 or 5(or 7-11), imbricate, free or slightly joined at base, concave, becoming reflexed, caducous. Petals 4 or 5(-14), free or slightly joined at base, each with a thick and usually hairy scale inside at base. Disk and disk glands absent. Staminate flowers: stamens 5 to many (more than 100); filaments free, sometimes very short; anthers oblong to ovate-cordate, longitudinally dehiscent, connective often dilated; pistillode present or absent. Pistillate flowers: staminodes 5 to many, resembling stamens but anthers mostly reduced or absent; ovary superior, 1-loculed, placentas 3-6, each with several ovules; styles 3-6, short, or nearly absent; stigmas flattened, usually reflexed. Fruit baccate, globose, or ovoid, rarely elongate; pericarp thick and hard, or thin and brittle, exocarp fibrous or not, mesocarp light yellow, usually very hard, endocarp soft. Seeds several to many, angular-ovoid, packed in pulp; testa hard, striate; aril membranous; endosperm oily; cotyledons large and broad, leaflike, compressed-flat or folded.
In Chinese species: flowers to ca. 20 together in fascicles or cymes; stamens 5 to ca. 25; mature fruit globose.
Hydnocarpus kurzii (King) Warburg (in Engler & Prantl, Nat. Pflanzenfam. 3(6a): 21. 1893; Taraktogenos kurzii King, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 59: 123. 1890), described from Myanmar, was recorded as native to S Yunnan by Lai (FRPS 52(1): 9. 1999), although the present authors have seen no material.
According to Fl. Yunnan. (6: 254. 1995), Hydnocarpus alpinus Wight is cultivated in S Yunnan.
About 40 species: tropical Asia; three species in China.