growing in large, dense clumps on edges of salt marsh
De Soto Monument, Manatee County, Florida
Borrichia frutescens (I think). 3.5 cm across, ~60 cm tall, growing in a dense stand near the edge of a lagoon. I left it uncropped to show the leaves, but it's super in original size.
Borrichia frutescens is a species of flowering plant in the aster family known by the common names sea oxeye, sea oxeye daisy, bushy seaside tansy, and sea-marigold. In Veracruz it is called verdolaga de mar. It is native to the United States and Mexico, where it occurs along the Atlantic and Gulf Coasts. Its distribution extends from Virginia south to Florida and west to Texas in the US, and along the Mexican Gulf Coast to Yucatán....