inches and bears peaches on the main trunk though the stem be scarcely larger than a lead pencil."[162] Most of the examples named are from China but others can be found in every distinct region in which peaches have long been grown. Every well-marked geographical region in which the peach is grown comes, sooner or later, to have a type of varieties of its own; yet the universal stamp of the peach--of cultivated _Prunus persica_--is on them all. These facts imply two important things. First, the peach is an exceedingly flexible fruit, capable of being moulded to fit many conditions of environment; and, under cultivation, training, feeding and culture in unlike regions, soils and climates, may still be greatly improved and the improvements all intensified and augmented by crossing and selecting. Second, the peach, a gift to the world from China, has seemingly, in its centuries of cultivation by the Orientals, taken on sufficient immutability to make it one of the most stable of species, especially in its fruits. The many races and thousands of varieties are all best put in one species; many varieties come true to seed; and peaches from seed seldom "revert" to worthless forms as so many seedling fruits habitually do. Cultivated plants, as all who work with them know, differ widely in variability. Some, as corn, the cucurbits, and grapes and plums with their many species, are so variable as to be almost unmanageable in attempts to improve them; others, as the cereals, are quite too immutable for the best work of the breeder. The peach is neither a stone wall nor shifting sand in the matter of variability. CHAPTER II BOTANICAL AND HORTICULTURAL CLASSIFICATIONS OF THE PEACH PLACE OF THE PEACH IN THE GENUS PRUNUS