Description from Flora of China
Damnacanthus esquirolii H. Léveillé; D. formosanus (Nakai) Koidzumi; D. indicus var. formosanus Nakai; D. indicus var. lancifolius Makino; D. lancifolius (Makino) Koidzumi.
Shrubs, 0.3-1.5 m tall. Roots fleshy, moniliform. Branches densely hispidulous to hirtellous, sometimes becoming glabrescent, terete or sometimes 4-angled, with numerous persistent spines 3-20 mm. Petiole of developed leaves 0.5-3 mm, strigillose, hispidulous, or glabrescent; leaf blade drying stiffly papery to leathery and discolorous, ovate, cordiform, elliptic-ovate, elliptic, or broadly elliptic, 0.5-2(-3) × 0.5-1(-1.5) cm, adaxially glabrous, abaxially glabrous or sparsely hirtellous to strigillose along veins, base obtuse to rounded, truncate, or cordulate, sometimes oblique, margins entire and flat, apex acute; midrib thinly prominulous adaxially; secondary veins 2 or 3(or 4) pairs; stipules quickly fragmenting or caducous, interpetiolar, narrowly to broadly triangular, 0.3-1 mm, strigillose to glabrescent, acute to glandular-fimbriate. Inflorescences strigillose to hispidulous. Pedicels 0.5-8 mm. Calyx strigillose to glabrous; hypanthium portion turbinate, 1-1.5 mm; limb 0.8-2 mm, lobed for 1/4-4/5; lobes broadly triangular to narrowly triangular. Corolla white, glabrous outside; tube 7-9 mm; lobes elliptic to lanceolate-elliptic, 2.5-5 mm. Drupes 4-6 mm in diam. Fl. Mar-Jun, fr. Mar-Jan.
Naiki and Nagamasu (Amer. J. Bot. 91: 664-671. 2004) reported that populations they studied are either monomorphic, with only pin-type flowers, or distylous. Koidzumi (Acta Phytotax. Geobot. 3: 158. 1934) reported Damnacanthus lancifolius from Yunnan and treated D. esquirolii as a synonym of that name; these names were apparently overlooked by Y. Z. Ruan (in FRPS 71(2): 169. 1999).
Sparse or dense forests on hills or mountains, rocky thickets; 100-1500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [N and NE India, Japan, Korea].