They are closely related to the genus Mahonia, which is included within Berberis by some botanists.
Species diversity is in South America, Africa and Asia; Europe has a few species, and North America only two.
The genus is characterised by dimorphic shoots, with long shoots which form the structure of the plant, and short shoots only 1-2 mm long.
The leaves on long shoots are non-photosynthetic, developed into three-spined thorns 3-30 mm long; the bud in the axil of each thorn-leaf then develops a short shoot with several normal, photosynthetic leaves. These leaves are 1-10 cm long, simple, and either entire, or with spiny margins.
The berries are edible, and rich in vitamin C, with a very sharp flavour.
The thorny shrubs make harvesting them difficult.
Berries are often used in Asian and European rice pilaf recipies.
Some berberis species are known as Barberry and used for herbal medicine.