Stems 40-70(-90) cm; base often reddish, glabrous or puberulent. Leaves usually present on proximal 1/5 of stem at anthesis; basal leaves 0-3 at anthesis; cauline leaves 3-7 at anthesis; petiole 0.8-12 cm. Leaf blade round to pentagonal, 1.5-4 × 2-6 cm, nearly glabrous; ultimate lobes 3-13, width 3-20 mm (basal), 1-8 mm (cauline). Inflorescences (5-)10-25(-45)-flowered, open, narrowly pyramidal; pedicel 0.5-3(-7) cm, glabrous to puberulent; bracteoles 3-7 mm from flowers, green, linear, 3-6 mm, puberulent. Flowers: sepals dark blue, puberulent, lateral sepals spreading, 9-16 × 4-7 mm, spurs gently upcurved, ascending 30-45° above horizontal, 8-14 mm; lower petal blades elevated, exposing stamens, 3.5-6 mm, clefts 0.5-1.5 mm; hairs densest near junction of blade and claw above base of cleft, centered or on inner lobes, white. Fruits 9-16(-19) mm, 2.5-3(-4) times longer than wide, puberulent. Seeds: seed coat cells brick-shaped, cell margins straight, surfaces smooth. 2 n = 16. Flowering late spring-early summer. Slopes in oak forests; 400-1600 m; Calif. Delphinium umbraculorum is most often confused with D . patens subsp. hepaticoideum ; refer to discussion of that taxon for distinguishing features. Hybrids occur with D . parryi and D . patens subsp. montanum .