Bu gu zhi is an annual plant growing mainly in provinces of Henan, Anhui, Guangdong, Shanxi, Jiangxi and Sichuan in China. Psoralea (Psoralea Corylifolia) grows 50–90 cm tall. It has pale-purple flowers in short, condensed, axillary spikes. Its corolla is pale purple. The flowers are one-seeded fruits. The most distinctive feature is the occurrence of minute brown glands which are immersed in surface tissue on all parts of the plant.