The wild form of this world-wide-famous nut is, doubtless, quite different from the varieties with which we are familiar, for two thousand years or more of continuous cultivation and selections have greatly changed the character of these nuts, as well as the habit of the trees. The nuts from the wild trees are said to have a rather thick shell, and to be much smaller than the best of the improved cultivated varieties, or very like those we now obtain in China and Japan. The Persian walnut, in its many varieties, has been planted almost everywhere in Europe as far north as Warsaw, but does not appear to have run wild and become naturalized, as with many other kinds of fruit and forest trees. In Great Britain it has probably been cultivated ever since the invasion of the country by the Romans, although a much later date is named by some of our modern horticultural authorities. Dodoens (1552), Gerarde (1597), Parkinson (1629), and other of our early authors of works on cultivated plants, speak of the Persian walnut as common in various countries of Europe, Great Britain included. John Evelyn, in his "Sylva" (1664), says: "In Burgundy, walnut trees abound where they stand, in the meadows of goodly lands, at sixty and a hundred feet distance, and so far as hurting the crop, they are looked upon as great preservers, keeping the ground warm, nor do the roots hinder the plow." Evelyn, no doubt, had read what Pliny had said on this point, viz.: "Even the oak will not thrive near the walnut tree; which, if it be true, may be owing to the interference of their roots in the subsoil; but it is certain that neither grass nor field nor garden crops thrive well under the walnut." Evelyn was far too good a gardener and close observer to fall into the error of attributing noxious properties to the walnut tree, although Pliny's assertion, which has no foundation beyond his imagination, has been many times repeated in these days of supposed general intelligence. Small plants may fail, under the shade of large trees, or when deprived of moisture by the roots of such trees, but the walnut is no exception to the rule; in fact, such deep-rooted kinds are less injurious than those with roots nearer the surface. Evelyn, in continuing his account of the walnut in Germany, says: "Whenever they fell a tree, which is only the old, decayed, they always plant a young one near him, and, in several places betwixt Hanau and Frankfort, no young farmer whatsoever is permitted to marry a wife till he bring proof that he is a father of such a stated number of walnut trees; and the law is inviolably observed to this day, for the extraordinary benefit which this tree affords the inhabitants."