[ noun ] any of numerous cultivated plants of the genus Delphinium <noun.plant>
Larkspur \Lark"spur\, n. (Bot.) A genus of ranunculaceous plants ({Delphinium}), having showy flowers, and a spurred calyx. They are natives of the North Temperate zone. The commonest larkspur of the gardens is {Delphinium Consolida}. The flower of the bee larkspur ({Delphinium elatum}) has two petals bearded with yellow hairs, and looks not unlike a bee.
But when they were allowed to mingle with untrained cattle that ate larkspur, the trained cows started eating it too.