Annuals. Stems erect, 1-3 dm. Cauline leaves: blade ovate to spatulate, margins crenate, dentate, or sinuate (not pinnatifid). Racemes usually 1-2 dm, rarely longer; rachis not geniculate. Fruiting pedicels 2.5-7 mm. Flowers: sepals ca. 4 mm, lateral pair not saccate basally; petals white or lavender, 5.3-8 × 1.3-2.6 mm, claw distinct. Fruits (terete or 4-angled), lanceoloid, 14-22 × 3-4 mm, (constricted at articulation of segments); proximal segment terete, long-cylindrical, (5-8.5 mm); terminal segment fusiform, (9-15 mm, beak conic), apex acute. Seeds: cotyledons accumbent. 2n = 18.

Flowering spring-fall. Sandy shores; ca. 0 m; Fla., La., Tex.

Cakile constricta is disjunct in Florida (not known from the Keys or southwestern Florida, where immature plants of C. lanceolata subspp. fusiformis and pseudoconstricta may be confused with it).