Brassica oleracea is the species of plant that includes many common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels sprouts, savoy, and Chinese kale. In its uncultivated form it is known as wild cabbage. It is native to coastal southern and western Europe. Its tolerance of salt and lime and its intolerance of competition from other plants typically restrict its natural occurrence to limestone sea cliffs, like the chalk cliffs on both sides of the English Channel.
Wild B. oleracea is a tall biennial plant, forming a stout rosette of large leaves in the first year, the leaves being fleshier and thicker than those of other species of Brassica, adaptations to store water and nutrients in its difficult growing environment. In its second year, the stored nutrients are used to produce a flower spike 1 to 2 metres (3–7 ft) tall bearing numerous yellow flowers.
Brassica (pron.: // brás-si-ca) is a genus of plants in the mustard family (Brassicaceae). The members of the genus are collectively known as cruciferous vegetables, cabbages, or mustards. Crops from this genus are sometimes called cole crops, which is derived from the Latin caulis, meaning stem or cabbage.
Common types of brassica used for food include cabbage, cauliflower, broccoli, Brussels sprouts, and some types of seeds. The genus is known for containing many important agricultural and horticultural crops. It also includes a number of weeds, both wild taxa and escapees from cultivation. It includes over 30 wild species and hybrids, and numerous additional cultivars and hybrids of cultivated origin. Most are annuals or biennials, but some are small shrubs. Due to their agricultural importance, Brassica plants have been the subject of much scientific interest. Six particularly important species (Brassica carinata, B. juncea, B. oleracea, B. napus, B. nigra and B. rapa) are derived by combining the chromosomes from three earlier species, as described by the Triangle of U theory.