Helianthus debilis is a species of sunflower known by the common names
cucumberleaf sunflower,
beach sunflower,
weak sunflower, and
East Coast dune sunflower. It is native to the United States, where it can be found along the Atlantic and Gulf Coasts. It is known elsewhere as an introduced species, such as South Africa, Australia, Taiwan, Slovakia, and Cuba.
(Wikipedia)