Description from Flora of China
Trees small, rarely shrubs, deciduous, to 10 m tall, spinose or unarmed. Bark brown or gray-brown, with long reduced branches, without buds; branchlets (new branches) purple-red or gray-brown, flexuose, smooth, with 2 stipular spines or not; long spines erect, to 3 cm, stout; short spines recurved, developed from old branches; annual branchlets pendulous, green, solitary or 2-7-fascicled on short shoots. Stipular spines slender, caducous; petiole 1-6 mm, or to 1 cm on long shoots, glabrous or sparsely puberulent; leaf blade abaxially pale green, adaxially dark green, ovate, ovate-elliptic, or elliptic-oblong, 3-7 × 1.5-4 cm, papery, abaxially ± puberulent on major veins or glabrous, adaxially glabrous, 3-veined from base, base slightly asymmetric, subrounded, margin crenate-serrate, apex obtuse or rounded, rarely acute, mucronulate. Flowers yellow-green, bisexual, 5-merous, glabrous, solitary or 2-8 crowded in axillary cymes, shortly pedunculate. Pedicel 2-3 mm. Sepals ovate-triangular, adaxially distinctly keeled. Petals obovate, ca. as long as stamens, clawed at base. Disk orbicular, thick, fleshy, 5-lobed. Ovary basally slightly immersed in disk; style 2-cleft to half. Drupe red at maturity, turning red-purple, oblong or narrowly ovoid, 2-3.5 cm, (0.5-)1.5-2 cm in diam.; mesocarp fleshy, thick, sweet- or sour-tasting; stone acute or obtuse at both ends, 2-loculed, 1- or 2-seeded; fruiting pedicel 2-5 mm or longer. Seeds compressed-orbicular, ca. 1 × 0.8 cm, Fl. May-Jul, fr. Aug-Oct. 2n = 24*, 36*, 48*.
Kirkbride et al. (Taxon 55: 1049-1050. 2007 ["2006"]) proposed the name Ziziphus jujuba for conservation against the paratautonym Z. zizyphus.
Ziziphus jujuba f. tortuosa C. Y. Cheng & M. J. Liu (J. Hebei Agric. Univ. 17(4): 7. 1994) is cultivated in gardens in Hebei, Henan, Jiangsu, S Shaanxi (Qin Ling), and Shandong. The plants are small trees with ascending, often tortuous branchlets without spines, long fruiting pedicels, and small drupes ca. 5 mm in diam. that resemble cucurbit fruits.
Ziziphus jujuba f. lageniformis (Nakai) Kitagawa (Lin. Fl. Manshur. 313. 1939; Z. sativa Gaertner var. lageniformis Nakai, Rep. Exped. Manchoukuo, Sect. IV, 1: 8. 1934) was recorded in FRPS (48(1): 136. 1982) from Hebei and (as cultivated) Beijing. However, it could not be treated here because no material was seen by the authors.
● Mountains, hills, sunny dry slopes, plains, also widely cultivated; below 1700 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Yunnan, Zhejiang [cultivated in Africa, Asia, Europe, and North and South America].