Bu gu zhi is an annual plant growing mainly in provinces of Henan, Anhui, Guangdong, Shanxi, Jiangxi and Sichuan in China. However, it isn?t native to China but west Asia. The dried psoralea seeds appear mainly as flat ellipse but sometimes shape something like a kidney, 3 to 5mm long, 2 to 4mm in diameter, 1.5mm thick, with a dimple in the middle, and dark brown rough surface with fine reticulate wrinkles and dense glandular spots. The thin pericarp is hard to be peeled off from the testa. Inside there is one kernel and a pair of cotyledon, from light brown to yellowish-brown, and rich in oil. And it has a very light sweet smell and slightly bitter and pungent taste.