Shrubs , evergreen, (0.3-)0.5-2 m. Stems usually monomorphic, seldom with short axillary shoots. Bark of 2d-year stems brown or purple, glabrous. Bud scales 3-5 mm, deciduous. Spines absent. Leaves 5-7-foliolate; petioles 0.5-3 cm. Leaflet blades thick and rigid; surfaces abaxially dull, papillose, adaxially dull, glaucous; terminal leaflet stalked, rarely sessile in a few leaves, blades 2.2-8.8 × 1.8-6 cm, 1.2-2 times as long as wide; lateral leaflet blades elliptic to oblong or oblong-ovate, 1-3-veined from base, base obtuse or truncate, margins strongly crispate, toothed, each with 3-8 teeth 2-8 mm tipped with spines to 2-4.8 × 0.4-0.6 mm, apex rounded or obtuse. Inflorescences racemose, dense, 25-50-flowered, 3-7 cm; bracteoles membranous, apex rounded or obtuse. Flowers: anther filaments with distal pair of recurved lateral teeth. Berries dark blue, at least sometimes glaucous, oblong-ovoid, 6-7 mm, juicy, solid. 2 n = 28. Flowering winter-spring (Mar-Apr). Dry rocky places in chaparral and open woodland; 600-1800 m; Calif. Berberis dictyota , B . amplectens , B . pumila , and B . wilcoxii are very similar, and the characters that separate them (height, glossiness and crispation of leaflets, and size and number of marginal teeth) are rather variable within the species. Berberis piperiana also belongs to this group, although it is usually more distinct because of its thinner leaflets with more slender, more numerous marginal spines. Berberis dictyota is resistant to infection by Puccinia graminis .
Medicinally, the Kawaiisu used a decoction of the root of Berberis dictyota to treat gonorrhea (D. E. Moermann 1986).