The innumerable varieties and sub-varieties of the turnip known as swedes, Kohl-rabi, etc., may be all attributed to one of the four species of Linnæus—_Brassica napus_, _Br. oleracea_, _Br. rapa_, _Br. campestris_—of which the two last should, according to modern authors, be fused into one. Other varieties of the species are cultivated for the leaves (cabbages), for the inflorescence (cauliflowers), or for the oil which is extracted from the seed (colza, rape, etc.). When the root or the lower part of the stem[60] is fleshy, the seed is not abundant, nor worth the trouble of extracting the oil; when those organs are slender, the production of the seed, on the contrary, becomes more important, and decides the economic use of the plant. In other words, the store of nutritious matter is placed sometimes in the lower, sometimes in the upper part of the plant, although the organization of the flower and fruit is similar, or nearly so. Touching the question of origin, we need not occupy ourselves with the botanical limits of the species, and with the classification of the races, varieties, and sub-varieties,[61] since all the _Brassicæ_ are of European and Siberian origin, and are still to be seen in these regions wild, or half wild, in some form or other. Plants so commonly cultivated and whose germination is so easy often spread round cultivated places; hence some uncertainty regarding the really wild nature of the plants found in the open country. Nevertheless, Linnæus mentions that _Brassica napus_ grows in the sand on the sea-coast in Sweden (Gothland), Holland, and England, which is confirmed, as far as Sweden is concerned, by Fries,[62] who, with his usual attention to questions of this nature, mentions _Br. Campestris_, L. (type of the _Rapa_ with slender roots), as really wild in the whole Scandinavian peninsula, in Finland and Denmark. Ledebour[63] indicates it in the whole of Russia, Siberia, and the Caspian Sea. The floras of temperate and southern Asia mention rapes and turnips as cultivated plants, never as escaped from cultivation.[64] This is already an indication of foreign origin. The evidence of philology is no less significant. There is no Sanskrit name for these plants, but only modern Hindu and Bengalee names, and those only for _Brassica rapa_ and _B. oleracea_.[65] Kæmpfer[66] gives Japanese names for the turnip—_busei_, or more commonly _aona_—but there is nothing to show that these names are ancient. Bretschneider, who has made a careful study of Chinese authors, mentions no _Brassica_. Apparently they do not occur in any of the ancient works on botany and agriculture, although several varieties are now cultivated in China.