A plant genus in the family berberidaceae. The common names of Barberry or oregon Grape are also used for mahonia. The similar-named Bayberry is the unrelated myrica. oregon Grape was classified by Pursh as a berberis but Nuttall claimed it is different enough to call it a new genus, mahonia. Botanists insist on this name while horticulturists stay with mahonia. They are shrubs with yellow wood and usually three-branched spines at the base of leafstalks. flowers are yellow, six-petaled and fruit is a berry with one to several seeds. Members contain berberine.