138 SYSTEMATIC POMOT.OGY 



tlie Domestica j)luins now orcupy in America is due to tlie fact 

 tliat they are not a(laj)te(l to tlie trans-Atlantie environment, 

 'i'lie j)Ium llii'ives hesi in an ('(juahle climate like that of eastern 

 and southern Hurope and of western America, and cannot en- 

 dure such extremes of heat and cold, wet and dry, as are found 

 in eastern and central America. Plant and fruit suffer also 

 from several ])arasites, as curculio, hlack-knot, leaf-blight and 

 plum-pocket. 



In North America, therefore, Domestica plums are confined to 

 favored localities on the Atlantic seaboard, the Great Lakes 

 regions, and the Pacific coast. In the first-named area they 

 thrive to a limited degree in Nova Scotia and parts of Quebec, 

 somewhat in central New England, and particularly well in the 

 fruit-growing sections of New York. South of New York but 

 few plums of this species are grown. The Domestica plums are 

 planted with indifferent success in southern Ontario and in 

 ^Michigan. In the great Valley of the Mississippi and in the 

 states of the Plains, this plum is hardly known. Westward in 

 the irrigated valleys of the Rocky Mountains and the Great 

 Basin, the climate is favorable and European plums are well 

 known. 



It is on the Pacific slope that the foreign plum reaches its 

 highest development in the New World. The trees in California, 

 Oregon, and Washington are \Qry thrifty, and the plums are of 

 large size, handsome appearance, and high quality. Both tree 

 and fruit in this favored region are free from most of the insect 

 and fungous troubles with which eastern plum-growers must 

 contend. Curculio and black-knot, scourges of eastern orchards, 

 are not troublesome on the western coast. In this region the 

 Domesticas, practically the only plums cultivated, succeed on 

 either irrigated or naturally watered lands. 



197. Groups of plums. — Plums fall into five natural groups, 

 more distinct than those of the peach, but becoming less so 

 as breeders of new varieties cross and recross them. These 

 groups help materially in classification and all of them are 

 readily recognized by plum-growers. 



(1) The Reine Claude or Green Gage plums. — This group is 

 so distinct that it is often given as a sub-species, and fruit- 

 growers speak of its varieties as Green Gages as if it were quite 



