Shrubs , evergreen, 0.3-1.6(-7) m. Stems usually monomorphic, seldom with short axillary shoots. Bark of 2d-year stems grayish brown, glabrous. Bud scales 3-7 mm, deciduous. Spines absent. Leaves (3-)5-13-foliolate; petioles 0.5-4.5(-7.5) cm. Leaflet blades thin and ± rigid or flexible; surfaces abaxially glossy, smooth, adaxially glossy, green; terminal leaflet stalked, blade 2.6-6.2 × 2-4.5 cm, 1.3-1.9 times as long as wide; lateral leaflet blades elliptic to ovate or broadly lanceolate, 1(-3)-veined from base, base broadly obtuse, truncate, or weakly cordate, margins plane to crispate, toothed, each with 5-22 teeth 0-2 mm tipped with spines to 1-3 × 0.1-0.3 mm, apex acute to rounded-obtuse. Inflorescences racemose, dense, 25-50-flowered, 2-9 cm; bracteoles membranous, apex rounded to broadly acute, sometimes apiculate. Anther filaments with distal pair of recurved lateral teeth. Berries blue, glaucous, oblong-ovoid to subspheric, 6-7 mm, juicy, solid.
Berberis pinnata is very similar to B. aquifolium, and the two are sometimes difficult to separate. Some authors have used the spacing of the lateral leaflets (said to be contiguous or imbricate in B. pinnata and remote in B. aquifolium) to separate them, but the leaflets are often remote in both species and may be contiguous in B. aquifolium.
Berberis pinnata is resistant to infection by Puccinia graminis .
Shrubs , self-supporting or clambering, 1-7 m. Leaflets thin and flexible; lateral leaflet blades lance-oblong or elliptic, margins plane or weakly undulate, marginal teeth tipped with spines to 1-1.6 × 0.1-0.2 mm. Inflorescences 6-9 cm.
Flowering winter (Mar). In shade beneath trees, pine and pine-oak forest; of conservation concern; 100-450 m; Calif.
Berberis pinnata subsp. insularis is endemic to the Channel Islands. Specimens of B . pinnata from the coast north of Santa Barbara often show some characteristics of subsp. insularis .
Shrubs , self-supporting, 0.3-1.6 m. Leaflets thin but ± rigid; lateral leaflet blades ovate to broadly lanceolate, margins undulate or crispate, marginal teeth tipped with spines to 1.2-3 × 0.2-0.3 mm. Inflorescences 2-5 cm.
Flowering winter-spring (Feb-May). Exposed rocky openings in woods and shrubland; 0-1200 m; Calif., Oreg.; Mexico (n Baja California).
