YELLOW EGG 386 THE PLUMS OF NEW YORK CHAPTER I EDIBLE PLUMS THE GENUS PRUNUS The great genus Prunus includes plums, cherries, almonds, apricots, peaches, and the evergreen cherries or cherry laurels. Its widely distributed species number a hundred or more for the world, nearly all of which belong north of the equator. The species of the genus are widely distributed in both the eastern and western hemispheres, the flora of eastern America and of western Asia being especially rich in species and individuals. For most part the species of Prunus belong to the Temperate Zone, but several of the evergreen cherries, usually grouped in a section under Laurocerasus, are found in the tropics and sub-tropics. The species cultivated for their edible fruits are found only in the Temperate Zone of the Northern Hemisphere. Of these the peach and the almond are believed to have come from eastern and southeastern Asia; the apricot is thought to be a native of northern China; the wild forms of the cultivated cherries are Eurasian plants, very generally distributed in the regions to the northward where the two continents meet. The habitats of the cultivated plums are given in detail in the text that follows, as Asia, Europe and America. Presumably the genus had its origin in some of the above regions; but where the center is from which the species radiated can never be known. Indeed, with present knowledge it cannot be said in what region Prunus has most species, is most productive of individuals, or shows highest development and greatest variability,—facts which might give some evidence as to the origin of the genus. It is probable that the greatest number of combinations of the above evidences can be shown for Asia and more especially for the Eurasian region, where Europe and Asia meet; yet North America has two score or more indigenous species about half of which are arborescent.