Styphnolobium

Styphnolobium is a small genus of three or four species of small trees and shrubs in the subfamily Faboideae of the pea family Fabaceae, formerly included within a broader interpretation of the genus Sophora. It was recently assigned to the unranked, monophyletic Cladrastis clade. The species of Styphnolobium differ from Sophora in lacking the ability to form symbioses with rhizobia (nitrogen fixing bacteria) on their roots. They also differ from the genus Calia (mescalbeans) in having deciduous leaves and flowers in axillary, not terminal, racemes. The leaves are pinnate, with 9–21 leaflets, and the flowers in pendulous racemes similar to those of the black locust. Necklacepod is a common name for plants in this genus.