There are several kinds of turnips; but of these the common white, or Norfolk turnips, and the Ruta-baga, or Swedish turnips, are the principal. The latter, which indeed constitute a distinct species, are generally of a yellowish colour, and are so hardy as to suffer no injury even from the most intense cold; but their substance is so compact as sometimes to break the teeth of sheep which feed upon them.
189. The COMMON CABBAGE (Brassica oleracea) is a well-known plant, the original stock of which grows on cliffs by the seaside, in Kent, Cornwall, Yorkshire, and Wales.
This wild plant is likewise the original of the various kinds of colewort, borecole, cauliflower, and brocoli.
The effects of cultivation on the cabbage are very remarkable. In the wild plants the leaves are extended: but in the common garden cabbage they are set so close together as to lie upon each other, almost like the scales of a bulb, and, increasing in compactness as they increase in size: those in the interior being excluded from the effects of the light, do not assume a green, but are of yellow colour.
Other plants of this species form their stalks into a head, as the cauliflower and brocoli; and others grow, in a natural way, without forming either their leaves or stalks into heads, as the coleworts, or Dorsetshire kale, the borcoles, turnip-rooted cabbage, and others.
In some parts of England, cabbages of different kinds are much cultivated as food for cattle, and they succeed well in rich and finely prepared land. The seed is sown in February or March. In April or May the young plants are taken out, and set in rows, at a little distance from each other; and, in the ensuing autumn and winter, the cabbages afford a valuable stock of food.
All the kinds of cabbage are useful for domestic purposes; and some of them afford a peculiarly sweet and delicate food. An agreeable pickle is made of them, and the Germans, and people of other northern countries of the Continent, prepare from them a favourite food called sour-crout. These plants were known to, and much used by, the ancient Greeks and Romans.
Cabbages are biennial plants, or are sown one year, produce seed in the ensuing year, and then die.