The varieties of the cultivated beets are commonly [71] included in four subspecies. The two smallest are the salad-beets and the ornamental forms, the first being used as food, and ordinarily cultivated in red varieties, the second being used as ornamental plants during the fall, when they fill the beds left empty by summer flowers, with a bright foliage that is exceedingly rich in form and color. Of the remaining subspecies, one comprises the numerous sorts cultivated as forage-crops and the other the true sugar-beets. Both of them vary widely as to the shape and the size of the roots, the quality of the tissue, the foliage and other characteristics. Some of these forms, no doubt, have originated during culture. Most of them have been improved by selection, and no beet found in the wild state ever rivals any cultivated variety. But the improvement chiefly affects the size, the amount of sugar and nutrient substances and some other qualities which recur in most of the varieties. The varietal attributes themselves however, are more or less of a specific nature, and have no relation to the real industrial value of the race. The short-rooted and the horn-shaped varieties might best be cited as examples. The assertion that the sundry varieties of forage-beets are not the result of artificial selection, [72] is supported in a large measure by the historic fact that the most of them are far older than the method of conscious selection of plants itself. This method is due to Louis Vilmorin and dates from the middle of the last century. But in the sixteenth century most of our present varieties of beets were already in cultivation. Caspar Bauhin gives a list of the beets of his time and it is not difficult to recognize in it a large series of subspecies and varieties and even of special forms, which are still cultivated. A more complete list was published towards the close of the same century by Olivier de Serres in his world-renowned "Theatre d'Agriculture" (Paris, 1600). The red forage-beets which are now cultivated on so large a scale, had been introduced from Italy into France only a short time before. From this historic evidence, the period during which the beets were cultivated from the time of the Romans or perhaps much later, up to the time of Bauhin and De Serres, would seem far too short for the production by the unguided selection of man of all the now existing types. On the other hand, the parallelism between the characters of some wild and some cultivated varieties goes to make it very probable that other varieties have been found in the same way, some in this country and others in that, [73] and have been taken into cultivation separately. Afterwards of course all must have been improved in the direction required by the needs of man.