_Prunus cerasus_ is the Sour Cherry, or Pie Cherry, of many languages--grown and esteemed in temperate climates the world over and probably the most widely distributed of all tree fruits. The species is found truly wild, as we have set forth in detail in the following chapter, in southwestern Asia and southeastern Europe. It is a frequent escape from cultivation, multiplying from seed distributed by birds or human agencies or growing from suckers which spring so freely from the roots as to make the species unfit for a stock in orchard work. The number of cultivated varieties of _Prunus cerasus_ listed in _The Cherries of New York_ is 270. Sour Cherries cultivated for their fruits constitute two distinct groups, each of which is again divided into many varieties. The two groups vary more or less in both tree and fruit but have a constant difference only in a single, very easily distinguished character--the juice in the fruits of one is red, in the other it is colorless. The cherries with colorless juice are the Amarelles, from the Latin for bitter, a term probably first used by the Germans but now in general use wherever these cherries are grown, though the English often designate them as Kentish cherries and the French as Cerisier Commun. These Amarelles are pale red fruits, more or less flattened at the ends. Despite the derivation of the name Amarelle, they have less bitterness than the other group of varieties of the Sour Cherry. They are also less acid than the darker colored cherries and are therefore more suitable for eating out of hand while the dark colored cherries are almost exclusively culinary fruits. The common representatives of this group are Early Richmond, Montmorency and the various cherries to which the word Amarelle is affixed, as the King Amarelle and the Späte Amarelle.