Delphinium bicolor subsp. bicolor
Flowers: sepals dark blue to purple, lateral sepals 16-21 × 6-11 mm, spurs 13-18 mm; lower petal blades with cleft less than 2 mm; hairs usually white.
Phenology: Flowering late spring–early summer.
Habitat: Dry meadow edges, sage scrub, open woodlands and edges, not on soils derived from limestone
Elevation: 600-3100 m
Alta., B.C., Sask., Idaho, Mont., Nebr., N.Dak., S.Dak., Wyo.
Rydberg's Delphinium bicolor var. montanense tends to have more pubescence and larger flowers but is otherwise typical and apparently fully intergrades with D. bicolor subsp. bicolor. Often referred to as one of the low larkspurs in poisonous-plant literature, the plant is abundant on some ranges and is the cause of some livestock poisonings.