n. Any plant of the genus Helianthus; -- so called probably from the form and color of its flower, which is large disk with yellow rays. The commonly cultivated sunflower is Helianthus annuus, a native of America. [ 1913 Webster ]
(n) annual sunflower grown for silage and for its seeds which are a source of oil; common throughout United States and much of North America, Syn. Helianthus annuus, mirasol
(n) slender hairy plant with few leaves and golden-yellow flower heads; sandy desert areas of southeastern California to southwestern Utah and western Arizona and northwestern Mexico, Syn. Gerea canescens
(n) any plant of the genus Tithonia; tall coarse herbs or shrubs of Mexico to Panama having large flower heads resembling sunflowers with yellow disc florets and golden-yellow to orange-scarlet rays, Syn. tithonia
(n) whitish hairy plant with featherlike leaves and a few stout stems each bearing an especially handsome solitary large yellow flower head; mountainous regions north central United States, Syn. Tetraneuris grandiflora, alpine sunflower, Hymenoxys grandiflora