12. Ziziphus rugosa Lamarck, Encycl. 3: 319. 1789.
皱枣 zhou zao
Shrubs or small trees, evergreen, to 9 m tall, spinose. Young branches densely ferruginous or yellow-brown tomentose; old branches red-brown, scabrous, striate, with conspicuous lenticels. Stipular spines 1(or 2), recurved, purple-red, 3-6 mm; petiole short, 5-9 mm, stout, densely yellow-brown tomentose; leaf blade broadly ovate or broadly elliptic, 8-11 × 4.5-9.5 cm, papery or subleathery, abaxially densely ferruginous or yellow-brown tomentose, adaxially at first villous, gradually glabrescent or later sparsely pubescent in vein axils, 3-5-veined from base, midvein with 2-5 pairs of secondary veins, veins prominent abaxially, impressed adaxially, base subcordate or rounded, oblique, margin serrulate, apex rounded. Inflorescences to 20 cm. Flowers green, densely pubescent, few to 10 in terminal or axillary large cymose panicles or cymose racemes; peduncles 5-12 mm. Pedicel ca. 2 mm, densely ferruginous tomentose. Sepals triangular, subequal to calyx tube, abaxially ferruginous tomentose, adaxially slightly keeled, apex acute. Petals absent. Disk orbicular, rather thick, 5-lobed, outer rim inconspicuous. Ovary globose, densely tomentose, to ca. 1/3 immersed in disk; styles deeply 2-cleft or 2-cleft to half. Drupe orange, turning black at maturity, obovoid-globose or subglobose, 9-12 mm, 8-10 mm in diam., hairy, gradually glabrescent, with persistent tube at base; fruiting pedicel 7-10 mm, tomentose; endocarp fragile-crustaceous; stone 1-loculed, 1-seeded. Seeds red-brown, globose, 6-7 × 6-7 mm. Fl. Mar-May, fr. Apr-Jun. 2n = 24.
Sparse forests and thickets on hills, sunny places on mountains; below 1400 m. Hainan, S and SW Yunnan [India, Laos, Myanmar, Sri Lanka, Thailand, Vietnam].
This species is an important host for the parasitic scale insect, Laccifer lacca (lac insect).