The explanation is probably a very simple one. Every weed which did not bloom and seed exactly at the right time was killed and left no seed. This encouraged the others, who have gradually brought about the neat little arrangements above described. A process of selection has been at work. Those that would not modify their arrangements to suit new methods of farming have been suppressed. But it is in some of the cultivated plants themselves that one sees the most extraordinary results of selection. The Wild Cabbage is still to be found on sea-cliffs on the south-western coast of England, and the Wild Turnip occasionally occurs in fields. There is nothing particularly interesting or attractive about either of them. Yet from the one has been produced cabbage, cauliflower, seakale, brussels sprouts, broccoli, and kohlrabi; and the other has given the endless varieties of turnips. For the most part these extraordinary changes have been brought about in a perfectly straightforward way, by just choosing the biggest and finest sorts for seed. Some of the feats performed by gardeners in this way are almost incredible. A United States seedsman evolved the idea of a perfect bean from his inner consciousness. It had a particular shape which he described to a noted grower of beans. Two years later his ideal bean was produced! The growers of pineapples used to have a great deal of difficulty on account of the pineapple cuttings becoming unhealthy. Sometimes 63 per cent. were more or less diseased. Then certain growers began to carefully select disease-proof pineapples, and finally reduced the percentage of diseased cuttings to four per cent. Another French observer (M. Roujon) by continually selecting the smallest seeds, was able to obtain corn only eight inches high. But by far the most interesting and important researches have been those dealing with roots and tubers. Several people have, in fact, done in a few years what it took primitive man centuries to accomplish. Thus, in 1890, E. v. Proskowetz obtained some seeds of the wild Sea-beetroot which is found on the south coast of France. By very careful selection he was able in the year 1894 to get good beetroots quite like the ordinary cultivated ones. These were biennials (not annuals like the wild plant), and had a large percentage of sugar--16·99 per cent. This was by selection in good and fertile soil.[125] Vilmorin also obtained quite good carrots in the fourth generation by cultivating the wild form in rich and good soil, and selecting the best. [125] Perceval, _Agricultural Botany_. In fact there are in natural wild plants great differences between individuals, and when such plants are cultivated in good soil, where they have far more to eat than they require, the result is that they produce extraordinary and monstrous types.