Root bark of Berberis vulgaris L., Berberidaceae. Habit. Europe and Western Asia; also U.S. (New England States, Pennsylvania and Virginia). Constit. Berberine, berbamine, oxyacanthine, tannin, wax, fat, resin. Ref: Neugebauer, Brunner, Pharm. Zentralhalle 80, 113 (1939).