A species of flowering plant in the family Berberidaceae, native to western North America. M. aquifolium grows to 1–2 m (3 ft 3 in–6 ft 7 in) tall by 1.5 m (5 ft) wide, with pinnate leaves up to 30 cm (12 in) long, each leaf made up of spiny leaflets. The leathery leaves resemble holly and the stems and twigs have a thickened, corky appearance. The flowers, borne in dense clusters in late spring, are yellow, and are followed by spherical dark dusty blue berries. Some authors place Mahonia in the barberry genus, Berberis. The Oregon-grape is not related to true grapes, but gets its name from the purple clusters of berries whose color and slightly dusted appearance are reminiscent of grapes.