Cabbage, the common name for Brassica oleracea, especially for those cultivated varieties that have their leaves uncut and uncurled and overlapping so as to form a head or heart. B. oleracea capitata, the common cabbage, was introduced into England by the Romans, into Scotland in the time of Cromwell. Its heart is generally blanched. In Germany it is shredded, salted, and fermented for winter use, under the name of sauer kraut. The red variety, B. oleracea rubra, is grown for pickling. The savoy is B. oleracea bullata, having its leaves raised in small "bullate" swellings between the veins. B. oleracea costata is the large-ribbed cabbage or couve tronchuda of Trauxuda in Portugal, of which the mid-rib is eaten. Cabbages are improved by being slightly touched by frost. Forms with loosely-arranged leaves (acephala) are known as borecole or cow-cabbage. In Jersey cabbages are grown to a considerable height by stripping off their lower leaves, and are made into walking-sticks.