American sea rocket

Cakile edentula, the American sea rocket, is a fleshy annual herb in the Brassicaceae native to sandy and gravelly beaches and lakeshores from Labrador and the Atlantic coast south to South Carolina, around the Great Lakes, and locally on the Pacific shore. Plants grow 15 to 60 cm tall, with much-branched, succulent, glabrous stems and obovate to spatulate, coarsely toothed or shallowly pinnatifid, thick fleshy leaves 2 to 7 cm long. Small four-petalled flowers, pale lilac to white and about 6 to 8 mm across, are borne in elongating racemes from June to September. The diagnostic fruit is a fleshy, two-jointed silique: the upper segment is corky, beaked, and breaks free to float on seawater, dispersing the seed across long distances; the lower segment remains on the parent plant. The species is a pioneer of unstable foredunes and strandlines.