Description from Flora of China
Shrubs or small to medium-sized trees, deciduous or rarely evergreen, often spinose. Branches opposite or alternate, unarmed or terminating in a woody spine; winter buds naked (R. subg. Frangula) or with scales (R. subg. Rhamnus). Leaves opposite or alternate, rarely fasciculate on short shoots; stipules mainly subulate, caducous, rarely persistent; leaf blade always undivided, pinnately veined, margin serrate or rarely entire. Flowers mostly yellowish green, small, bisexual or unisexual, rarely polygamous, solitary or few fascicled in axillary cymes, cymose racemes, or cymose panicles. Calyx tube campanulate to cup-shaped; sepals 4 or 5, ovate-triangular, adaxially ± distinctly keeled. Petals 4 or 5, rarely absent, shorter than sepals, cucullate to hooded, often enfolding stamens, base shortly clawed, apex often 2-fid. Stamens 4 or 5, surrounded by and equaling petals or shorter; anthers dorsifixed. Disk thin, adnate and lining calyx tube. Ovary superior, globose, free, 2-4-loculed; styles ± deeply 2-4-cleft. Fruit a 2-4-stoned, berrylike drupe, obovoid-globose or globose; stones indehiscent or ventrally dehiscing. Seeds obovoid or oblong-obovoid, unfurrowed or abaxially or laterally with a ± long, narrow to gaping, often distinctly margined furrow; endosperm fleshy.
The fruit of most species contain yellow dye; the seeds contain rich protein and oils and are used for making lubricating oil, printing ink, and soap. The roots and leaves of a few species are used medicinally.
Rhamnus coriaceifolia H. Léveillé (Repert. Spec. Nov. Regni Veg. 12: 535. 1913, "coriaceifolius") was referred by Lauener (Notes Roy. Bot. Gard. Edinburgh 27: 279. 1967) to Sideroxylon wightianum Hooker & Arnott, the basionym of Sinosideroxylon wightianum (Hooker & Arnott) Aubréville in the Sapotaceae (see Fl. China 15: 212. 1996).
Rhamnus myrtillus H. Léveillé (Repert. Spec. Nov. Regni Veg. 12: 535. 1913) is a synonym of Myrsine africana Linnaeus in the Myrsinaceae (see Fl. China 15: 36. 1996).
Rhamnus pasteurii H. Léveillé (Monde Pl. 18: 31. 1916, "pasteuri") is a synonym of Gardneria multiflora Makino in the Loganiaceae (see Fl. China 15: 328. 1996).
The following species were described from China but could not be treated here because no material was seen by the authors:
Rhamnus calcicola Q. H. Chen (Acta Bot. Yunnan. 7: 413. 1985, "calcicolus"), described from Guizhou.
Rhamnus dalianensis S. Y. Li & Z. H. Ning (Bull. Bot. Res., Harbin 8(2): 95. 1988), described from Liaoning.
Rhamnus daliensis G. S. Fan & L. L. Deng (Sida 17: 680. 1997), described from Yunnan.
Rhamnus laoshanensis D. K. Zang (Bull. Bot. Res., Harbin 19: 371. 1999), described from Shandong.
Rhamnus mongolica Y. Z. Zhao & L. Q. Zhao (Novon 16: 158. 2006), described from Nei Mongol.
Rhamnus qianweiensis Z. Y. Zhu (Acta Bot. Boreal.-Occid. Sin. 6(2): 135. 1986), described from Sichuan.
Rhamnus serpyllifolia H. Léveillé (Repert. Spec. Nov. Regni Veg. 12: 282. 1913), described from Yunnan (not treated as a synonym by Lauener, Notes Roy. Bot. Gard. Edinburgh 27: 280. 1967).
Rhamnus viridifolia Liou (Ill. Fl. Lign. Pl. N.-E. China, 565. 1955), described from Liaoning.
About 150 species: temperate to tropical regions, mainly in E Asia and North America, a few species in Europe and Africa; 57 species (37 endemic) in China.