Gleditsia horrida Willdenow; G. macracantha Desfon­taines; G. officinalis Hemsley.

Trees or small trees, to 30 m tall. Branches grayish to deep brown. Spines robust, terete, conical, to 16 cm, often branched. Leaves pinnate, 10-18(-26) cm; petiolules 1-2(-5) mm, puber­ulent; leaflets (2 or)3-9 pairs, ovate-lanceolate to oblong, 2-8.5(-12.5) × 1-4(-6) cm, papery, abaxially slightly pubescent on midvein, adaxially puberulent, reticulate veinlets conspicu­ously raised on both surfaces, base rounded or cuneate, some­times slightly oblique, margin serrate, apex acute or acuminate, tip rounded, mucronate. Flowers polygamous, yellowish white, in axillary or terminal, puberulent racemes 5-14 cm. Male flowers: 9-10 mm in diam.; pedicels 2-8(-10) mm; receptacle deep brown, 2.5-3 mm, outside pubescent; sepals 4, triangular-lanceolate, ca. 3 mm, both sides pubescent; petals 4, oblong, 4-5 mm, puberulent; stamens (6-)8; rudimentary pistil ca. 2.5 mm. Bisexual flowers: 10-12 mm in diam.; pedicels 2-5 mm; sepals and petals similar to those of male flowers but longer; stamens 8; ovary hairy at base and on sutures; ovules numer­ous; stigma 2-lobed. Legume brown or reddish brown, curved, strap-shaped, 12-37 × 2-4 cm, straight or twisted, with slightly thick pulp, swollen on both surfaces, some legumes shorter and smaller, ± terete, 5-13 × 1-1.5 cm, without seeds; stipe 1-3.5 cm; valves leathery, often farinose. Seeds numerous, brown, shiny, oblong or elliptic, 11-13 × 8-9 mm. Fl. Mar-May, fr. May-Dec. 2n = 28*.

Specimens from Sichuan called "zhu ya zao," named as Gleditsia officinalis, with curved, small fruit without seeds, are an abnormal type and are referable to this species.

● Mountain slopes, forests, valleys, near roads; 200-2500 m. An­hui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hu­bei, Hunan, Jiangsu, Jiangxi, ?Qinghai, Shaanxi, Shanxi, Sichuan, Yun­nan, Zhejiang.