Description from Flora of China
Trees or shrubs, deciduous. Trunk and branches usually with stout, simple or branched spines. Leaves alternate, often clustered, simply paripinnate and bipinnate often on same plant; stipules caducous, small; rachis of leaves and pinnae sulcate; leaflets numerous, subopposite or alternate, base oblique or subsymmetrical, margin serrulate or crenate, rarely entire. Inflorescences axillary, rarely terminal, spikes or racemes, rarely panicles. Flowers polygamous or plants dioecious, light green or greenish white. Receptacle campanulate, outside pubescent. Calyx 3-5-lobed; lobes subequal. Petals 3-5, slightly unequal, ca. as long as or slightly longer than calyx lobes. Stamens 6-10, exserted, slightly flat, broad, with crisped hairs from middle downward; anthers dorsifixed. Ovary sessile or shortly stalked; ovules 1 to numerous; style short; stigma terminal. Legume ovoid or elliptic, flat or subterete.
Gleditsia medogensis C. C. Ni (Acta Phytotax. Sin. 25: 231. 1987), described from SE Xizang (Mêdog), could not be treated here because no material was seen by the present authors. Judging from the protologue, it may be conspecific with the variable G. japonica.
About 16 species: C and SE Asia, North and South America; six species (three endemic, one introduced) in China.
(Authors: Chen Dezhao (陈德昭 Chen Te-chao), Zhang Dianxiang (张奠湘); Kai Larsen)