Leptosyne maritima (Sea Dahlia or Beach Coreopsis) is a rare plant species in the Asteraceae (Sunflower) family. It was formerly included in the genus Coreopsis and some sources still refer to it by that name. This species is a perennial that grows 10-40 centimeters tall but sometimes to 80 centimeters (4 to 32 inches), from a fleshy taproot. The stems are hollow, fragile and often floppy. Plants bloom in late winter to early summer, with normally one or two flower heads per stem, on 15 to 30 centimeters long peduncles, but sometimes 4 or more flowers can be found per stem. It has foliage that is lobed and mostly linear in shape with lobes that are 5-30 millimeters long and 1-2 millimeters wide. The 12-20 millimeter long flower phyllaries number 12-13, sometimes more, and they are lance-shaped. Flower heads typically have 16-21 ray florets, and the laminae are 20-35+ millimeters long. The disc corollas are 5.5-7 millimeters long. Fruits are 6-7 millimeters long and oblong-rectangular in shape. Leptosyne maritima is native to a very small area of southern California and Baja California, where it typically grows on ocean bluffs and dunes at elevations under 100 ft.