Berberis aquifolium Pursh var. repens (Lindley) Scoggan; B. sonnei (Abrams) McMinn; Mahonia repens (Lindley) G. Don; M. sonnei Abrams

Shrubs , evergreen, 0.02-0.2(-0.6) m. Stems monomorphic, usually without short axillary shoots. Bark of 2d-year stems grayish or purplish brown, glabrous. Bud scales 3-8 mm, deciduous. Spines absent. Leaves (3-)5-7-foliolate; petioles (1-)3-9 cm. Leaflet blades thin and flexible; surfaces abaxially dull, papillose, adaxially dull, rarely glossy, somewhat glaucous; terminal leaflet stalked, blade 3.2-9.5 × 2.3-6 cm, 1.2-2.2(-2.5) times as long as wide; lateral leaflets ovate or elliptic, 1(-3)-veined from base, base rounded to obtuse or truncate, margins plane, toothed, with 6-24 teeth 0.5-3 mm tipped with spines to 0.6-2.8 × 0.1-0.25 mm, apex rounded, rarely obtuse or even broadly acute. Inflorescences racemose, dense, 25-50-flowered, 3-10 cm; bracteoles membranous, apex rounded to obtuse or broadly acute. Anther filaments with distal pair of recurved lateral teeth. Berries blue, glaucous, oblong-ovoid, 6-10 mm, juicy, solid. 2 n = 28.

Flowering spring (Apr-Jun). Open forest, shrubland, and grassland; 200-3000 m; Alta., B.C.; Ariz., Calif., Colo., Idaho, Minn., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., S.Dak., Tex., Utah, Wash., Wyo.

Berberis sonnei was described based on plants with relatively narrow, rather shiny leaflets collected by Sonne in Truckee, California. Subsequent collections from this population show the morphology typical of B . repens ; Sonne's collections evidently are an aberrant form of this species.

Berberis repens is resistant to infection by Puccinia graminis .

Various Native American tribes used preparations of the roots of Berberis repens to treat stomach troubles, to prevent bloody dysentary, and as a blood purifier; mixed with whiskey, it was used for bladder problems, venereal diseases, general aches, and kidney problems; and preparations made from the entire plant served as a cure-all and as a lotion for scorpion bites (D. E. Moermann 1986).