usually prickly, fruit-bearing bush of the genus Rubus (family Rosaceae), native chiefly to the north temperate regions of the Old and New World; the thornless blackberry is a modern development. The blackberry is particularly abundant in eastern North America and on the Pacific coast; in the British Isles and western Europe it is a common copse and hedge plant. The bush is characterized by its usually biennial, prickly, erect, semi-erect, or trailing stems; leaves with usually three or five oval, coarsely toothed, stalked leaflets, many of which persist through the winter; white, pink, or red flowers in terminal clusters; and black or red-purple fruits, each consisting of numerous drupelets adhering to a juicy core. The several trailing species of Rubus, which lack woody fibre in the stem, are commonly called dewberries (dewberry).