Chinese honey-locust

Gleditsia sinensis, the Chinese honey locust, is a deciduous tree of the legume family native to China, reaching some ten to fifteen metres in height. Its trunk and lower branches are conspicuously armed with stout, often branched woody spines. The leaves are pinnately compound, with numerous small oval leaflets giving a fine, feathery texture. Inconspicuous greenish-white flowers are borne in slender racemes and develop into large, flattened, leathery pods that turn dark brown to blackish at maturity and contain hard seeds embedded in a saponin-rich pulp. The tree grows in mixed woodland, valleys and along watercourses and has long been planted near villages. For more than two thousand years the saponin-laden pods served as a natural detergent, while the pods and the large thorns are valued medicinal materials; both are rich in triterpenoid saponins and flavonoids. The saponins make the plant tissues, especially the pods and seeds, irritant and toxic if misused.