Stems proximally sparsely puberulent, remainder ± glabrous. Leaf blades glabrous. Inflorescences nearly glabrous. Flowers: sepals spreading to erect, greenish white, hairs usually near apex only, lateral sepals 6-8 mm, spurs 7-10 mm; upper petals glabrous.

Flowering late spring. Usually on inland facing slopes in open woods; of conservation concern; 300-800 m; Calif.

Delphinium californicum subsp. interius is known from fewer than a dozen localities. It apparently hybridizes with D . hesperium subsp. pallescens .