is an uncommon species, found only in the Ajo and Kofa mountain ranges, in Arizona, where it inhabits shady places in canyons and rocky hillsides, and blooms late winter/early spring.
All leaves are trifoliate, with all three leaflets attached at the same point, at the tip of a pale green stalk up to 2 inches in length. Leaflets are dull green, on both surfaces, lined by three to five spiny lobes. There are no spines on the woody branches.
Flowers are arranged in relatively open clusters, of between six and 11; far fewer than some other berberis species. The all-yellow flowers consist of six sepals, six petals, six stamens and a central style. Fruits are round, juicy berries, dark blue to black.