Roots without elongate central axis; fascicles 2-8, ± horizontal. Stems 50-80 cm. Leaves mostly cauline at anthesis; distalmost petioles more than 5 mm. Leaf blade with 5 or more major divisions; ultimate lobes of midcauline leaf blades 5-15, width 2-6 mm. Flowers: sepals white to very pale blue. 2 n = 16. Flowering late winter-early summer. Prairies, sandy, loamy, or clay soils; 250-2000 m; Man.; Colo., Iowa, Kans., Minn., Mo., Nebr., N.Dak., Okla., S.Dak., Tex., Wis. Delphinium carolinianum subsp. virescens is known to hybridize with D . madrense and with D . wootonii .
Stem 4-12 dm, finely and often densely pubescent, often or usually glandular; lvs chiefly basal or below the middle of the stem, deeply dissected into linear segments mostly 2-5 mm wide; raceme elongate, virgate, the lower pedicels seldom over 1.5 cm; fls white, greenish- white, or bluish-white; spur 10-14 mm; upper pair of pet sometimes yellow; lower pet bifid, bearded; follicles 15-20 mm; seeds wingless, densely covered with projecting scales; 2n=16. Prairies and plains; N.D., s. Man., Minn., and w. Wis., s. to Ill., La., Tex., Colo., and N.M., and e. occasionally into c. Ky. and nw. Ga. May-July. (D. penardii) Perhaps better treated as a var. of D. carolinianum.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.