The sea beet (Beta vulgaris subsp. maritima) is a member of the family Chenopodiaceae, and is the wild ancestor of common vegetables such as beetroot, sugar beet, and Swiss chard. Its leaves have a pleasant texture and taste when served raw or cooked.

It is a perennial plant which grows up to 1.2 m, and flowers from July until September. Its flowers are hermaphroditic, and wind pollinated. It lives in the wild along some shores in Great Britain. It requires moist, well-drained soils, and does not tolerate shade.

It is a maritime plant able to tolerate relatively high levels of sodium in its environment.