Description from Flora of China
Trees, evergreen or semievergreen, rarely deciduous in dry season. Xylem with aromatic resin in intercellular resin canals. Branchlets with stipular scars, sometimes annular. Leaves simple, alternate; stipules persistent or caducous, large or small; leaf blade with lateral veins pinnate, margin entire or sinuate-crenate. Inflorescences few- or many-flowered, terminal or axillary racemes or panicles; flowers usually sweetly scented; bracts usually fugacious and minute, rarely persistent and large. Inflorescences, calyces, petals, ovary, and other parts usually with stellate, squamate, fascicled or free-standing hairs. Flowers bisexual, actinomorphic, contorted. Calyx lobes 5, free or united at base, imbricate in bud if not united. Petals 5, adnate or connate at base. Stamens (10-)15 to many, free from or connate to petals; filaments usually dilated at base; anthers 2-celled, with 2 pollen sacs per cell (Chinese species); connective appendages aristate, filiform or stout. Ovary superior, rarely semi-inferior, slightly immersed in torus, usually 3-loculed, each locule 2-, rarely many ovuled; ovules pendulous, lateral or anatropous. Fruit usually nutlike, sometimes capsular and 3-valved, 1(to many)-seeded, with persistent, variously accrescent calyx of which 2 or more lobes are usually developed into lorate wings. Seed exalbuminous; cotyledons fleshy, equal or unequal, applanate or ± folded or cerebriform, entire or laciniate; radicle directed toward hilum, usually included between cotyledons.
Tong Shaoquan & Tao Gouda. 1990. Dipterocarpaceae. In: Li Hsiwen, ed., Fl. Reipubl. Popularis Sin. 50(2): 113-131.
About 17 genera and 550 species: tropical Africa, Asia, and South America (in Asia, most species and genera in NW Borneo); five genera and 12 species (one endemic, one introduced) in China.
(Authors: Li Xiwen (李锡文 Li Hsi-wen), Li Jie (李捷); Peter S. Ashton)