1.2- Species Brassica oleracea L. + Overview Brassica oleracea is the species of plant that includes many common foods as cultivars, including cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, savoy, kohlrabi 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 limestoneseacliffs, like the chalk cliffs on both sides of the English Channel. Wild Brassica 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 oleracea, wild cabbage, is a species in the Brassicaceae (the cabbage or mustard family) from which numerous vegetable crops have been derived, including broccoli, cabbage, cauliflower, collards, Chinese broccoli, Brussels sprouts, kale, curly kale, and kohlrabi, among others. Although the varieties are so numerous as to complicate a general description, the plant is generally stout herbaceous annual, biennial, or occasionally perennial with smooth, glaucous (waxy), rounded lower leaves, which originated in Europe and has been cultivated since Roman times or before. It is most commonly grown in north temperate regions, as it requires a cool growing season and abundant moisture, and its numerous varieties are popular in home gardens. Brassica olearacea, along with the cultivars of Brassica juncea and Brassica rapa, have such a long history of cultivation and diversification that it can be difficult to ascertain and classify the relationships among species and varieties (or subspecies). Varieties of Brassica olearacea are generally placed into the following eight groups: 1) Acephala Group: Brassica oleracea var. acephala, which includes some types of kale, collards, palm cabbage, and Portuguese cabbage, all used for their leaves, which are generally used as a cooked vegetable or in soups, but are sometimes marinated in dressing and used as a salad. 2) Alboglabra Group: Brassica oleracea var. alboglabra, Chinese broccoli or Chinese kale, which produces fleshy stems and crowded flower buds; the stems, flower buds, and young leaves are generally used as a cooked vegetable and are typical in Asian stir fries, soups, and noodle dishes. 3) Botrytis Group: Brassica oleracea var. botrytris, cauliflower, including purple cultivars (Cape broccoli), as well as the pyramid-shaped Italian cultivars (Romanesco), which have large fleshy stems and flower buds that do not open; the stems and buds, which form heads, are served raw in salads or used as a cooked vegetable. 4) Capitata Group: Brassica oleracea var. capitata, which includes cabbage (sometimes referred to as white cabbage), red cabbage, and Savoy cabbage, in which the large, rounded leaves grow together densely together with a fleshy stem to form a “head,” which is used raw in salads, pickled or fermented (in the German sauerkraut as well as in numerous other regional dishes), or cooked as a vegetable in many northern European cuisines. 5) Gemmifera Group: Brassica oleracea var. gemmifera, Brussels sprouts, which forms numerous large axillary buds (where leaf joins stem), with leaves so densely packed as to form small heads, and numerous of these buds ascending a central stalk that can grow to 1 m (3 ft) tall; the buds are used as a cooked vegetable, featured in various typical French dishes. The large stem leaves may also be used as a cooked green. 6) Gongylodes Group: Brassica oleracea var. gongylodes, kohlrabi, which has a greatly enlarged, bulbous, above-ground stem, with the leaves often growing in a crown around the outer edge; the stem may be used raw in salads but is more typically cooked and prepared similarly to turnips or used in soups. The leaves may also be used as a cooked green. 7) Italica Group: Brassica oleracea var. italica, broccoli, which has thick fleshy stalks and a large head of densely packed flowerbuds; the stems are harvested while flower buds are still immature and tightly closed, and used raw or as a cooked vegetable. Broccoli is a highly nutritious vegetable, with a high vitamin C content and numerous other vitamins and minerals, while low in calories. 8) Tronchuda Group: Brassica oleracea var. sabellica, curly and Portuguese kales, which are short-lived perennials from which the leaves can be harvested for several years; the leaves are generally used as a cooked green, notably in Portuguese dishes including the traditional kale soup known as “caldo verde,” but may also be marinated in dressing and used raw in salads. Statistics on the production of this diverse group of vegetables are difficult to aggregate. The FAO tracks a category called “cabbages and other Brassica species,” which covers all the varieties of B. olearacea but includes related species as well. However, this category suggests at least the general level of commercial production of these vegetables, which the FAO estimated was 60 million metric tons worldwide in 2010, harvested from 2.1 million hectares. Leading producers were China, India, the Russian Federation, Japan and Korea; the U.S. ranked 9th in total production. Source: Brassica oleracea - http://eol.org/pages/583899/overview.