Perennial, erect, prickly shrub, up to 3-5 ft high, much branched. Stem and branches terete, glabrous; 2-3 or 4-armed simple spines with small stalk in the axils of leaves, whitish, 0.5-1.5 cm long. Leaves simple, decussate, 6-14 x 4-6 cm, ovate to broadly ovate, elliptic, acuminate, bristle-tipped, margin ciliate, base tapering, glabrous above, pubescent in young leaves. Flowers sessile, often solitary in lower axils. Corolla golden yellow, pubescent outside, bilipped. Capsules obpyriform, compressed with solid apical beak.