Stems 70-110(-150) cm; base reddish or not, glabrous, often glaucous. Leaves mostly on proximal 1/3 of stem, on proximal 1/5 at anthesis; basal leaves 0-4 at anthesis; cauline leaves 6-12 at anthesis; petiole 1-18 cm. Leaf blade ± pentagonal, 1-5 × 1.5-7 cm, glabrous; ultimate lobes 3-9, width 5-28 mm (basal), 3-18 mm (cauline). Inflorescences 20-35(-51)-flowered, usually dense; pedicel 0.3-1.5(-2.5) cm, glabrous; bracteoles 2-4 mm from flowers, green, linear, 1-2(-4) mm, nearly glabrous. Flowers: sepals white to light blue, glabrous, lateral sepals spreading to forward pointing, 8-12 × 3-5 mm, spurs straight to gently upcurved, ascending 30-60° above horizontal, 9-12 mm; lower petal blades slightly elevated, ± exposing stamens, 3-5 mm, clefts 1-2 mm; hairs centered, densest near base of cleft, white. Fruits 12-20 mm, 2.6-4 times longer than wide, glabrous. Seeds wing-margined; seed coat cells surfaces smooth.

Flowering summer. Rock outcrops in open coniferous woods; 2200-2800 m; Calif.

Delphinium inopinum is apparently endemic to a white metamorphic rock substrate in the Piute Mountains and southern Sierra Nevada. It is not known to hybridize with any other species, although D . patens subsp. montanum has been collected (when both were flowering) within 1 km of D . inopinum and probably occurs much closer. Delphinium inopinum is often confused with D . parishii subsp. pallidum and superficially resembles some white-flowered individuals of D . hansenii , as well as D . gypsophilum and D . hesperium subsp. pallescens . The massive roots with prominent buds readily distinguish D . inopinum from all of these. In addition, the pubescence found on D . hansenii will separate it from the glabrous D . inopinum . Leaves are rarely seen at anthesis near the base of the stem in D . hesperium subsp. pallescens ; they are present in D . inopinum .