larkspur, any north temperate, Old World annual of the genus Consolida of the buttercup family. Consolida species were formerly classified in the genus Delphinium, which includes similar annual, biennial, and perennial herbaceous plants of the northern temperate zone that are commonly called larkspurs or delphiniums. Plants of both genera are popular garden plants, especially favored for their blue-flowered varieties. In many cultivated larkspurs and delphiniums the spurred flowers, usually blue, pink, or white, rise in a spire above the deeply cut leaves. Most native North American delphinium species are poisonous to cattle. Larkspurs and delphiniums are classified in the division Magnoliophyta, class Magnoliopsida, order Ranunculales, family Ranunculaceae.