37. Rhamnus utilis Decaisne, Compt. Rend. Hebd. Seances Acad. Sci. 44: 1141. 1857.
冻绿 dong lü
Shrubs or small trees, dioecious, to 4 m tall, mainly spinose, rarely unarmed. Branches opposite to subopposite; young branches whitish to grayish pubescent, glabrescent, terminating in a bud or spine; old branches brown or purple-red, smooth. Leaves opposite to subopposite or fascicled on short shoots; stipules lanceolate, often pilose, persistent; petiole 0.5-1.5 cm, adaxially canaliculate; leaf blade abaxially yellow-green, adaxially dark green, shiny, elliptic, oblong, or obovate-elliptic, 4-15 × 2-6.5 cm, papery to subleathery, abaxially golden-yellow pubescent on veins, adaxially mostly glabrous, lateral veins 5 or 6(-8) pairs, prominent on both surfaces, base cuneate or rarely rounded, sometimes slightly asymmetric, margin finely serrate, apex acute. Flowers unisexual, 4-merous. Pedicels 5-7 mm, glabrous, white pilose, or gray pubescent. Calyx puberulent or glabrous. Petals present. Male flowers few fascicled in leaf axils or 10-30-fascicled at lower part of branchlets, with rudimentary pistil. Female flowers 2-6-fascicled in leaf axils or at lower part of branchlets; rudimentary stamens small; style long, 2-fid or cleft to half. Drupe black at maturity, globose or subglobose, with 2 stones, with persistent calyx tube at base; fruiting pedicel 5-12 mm, glabrous. Seeds abaxially-laterally with margined short furrow at base. Fl. Apr-Jun, fr. May-Aug.
Forests, thickets, mountains, hills, grassy slopes; below 3300 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shanxi, Sichuan, Zhejiang [Japan, Korea].
Oil extracted from the seeds is used for making lubricating oil. The fruit, bark, and leaves contain yellow dye.