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.
Calif., Oreg., Mexico (Baja California).
Subspecies 2 (2 in the flora).
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.
|1||Margins of leaf blade undulate or crispate, marginal spines to 1.2-3 × 0.2-0.3 mm; shrubs 0.3-1.6 m, self-supporting.||Berberis pinnata subsp. pinnata|
|1||Margins of leaf blade plane or weakly undulate, marginal spines to 1-1.6 × 0.1- 0.2 mm; shrubs 1-7 m, self-supporting or clambering over surrounding vegetation.||Berberis pinnata subsp. insularis|