thorny evergreen or deciduous shrub (Berberis) of family Berberidaceae; native to Asia, South and North America, Europe, and northern Africa; plants have yellow wood, six-petaled yellow or red flowers, three-branched spines on leafstalks; fruit is seeded black, yellow, or red berry; dyes extracted and jellies made from plants and fruits; other species include wintergreen barberry, American or Allegheny barberry, and Japanese barberry; some species may not be cultivated because they harbor a fungus that causes black stem rust in wheat.