- any of a number of composite plants having daisylike flowers with a dark center disk and usually yellow ray flowers, especially Rudbeckia hirta: the state flower of Maryland.
- any of several North American plants of the genus Rudbeckia, esp R. hirta, having flower heads of orange-yellow rays and brown-black centres: family Asteraceae (composites)
- a climbing plant, Thunbergia alata, native to tropical Africa but widely naturalized elsewhere, having yellow flowers with purple centres, grown as a greenhouse annual
