kale, borecole, and collards, common names for nonheading, hardy types of cabbage (var. acephala and sometimes others), with thick stems and curly leaves, belonging to the family Cruciferae (mustard family). They are grown for greens and, in Europe, for fodder. In the Channel Islands a tall fodder variety, known as Jersey kale, Jersey cabbage, or cow cabbage, grows to more than 7 ft (2.1 m). Kale (or kail) is a cool-weather crop—frost improves the flavor. In the United States the principal commercial growing regions are in Virginia and on Long Island. Kale is closest in form to the wild cabbage. In Scotland the word kale is used for cabbages of any kind. Sea kale is a European herb of another mustard genus Crambe, found along the northern coasts and often used as a potherb. Kale, borecole, and collards are all classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.