428 THE SURVIVAL OF THE UNLIKE. [XXVI. 



comparable climate. (Essay XV.) The east -coast 

 floras of the northern hemispheres are more closely 

 related than the more contiguous east and west- 

 coast floras. In fact, the plants of Europe are quite 

 as much like those of California in many particulars as 

 they .are like those of our Atlantic slope, a fact which 

 is again well illustrated in the similar horticultural 

 industries of our Pacific slope and central and south- 

 ern Europe. The only North American region in 

 which many of the characteristic European fruits 

 thrive unequivocally — as the wine grape, olive, wal- 

 nut, almond and others — is west of the Sierras, 

 although there is a tendency for this belt to extend 

 eastward through Texas and along the Gulf. The 

 Japanese plum is one of the many plants which prove 

 the similarity of east -Asian and east -American con- 

 ditions, and the dissimilarity of east -American and 

 European conditions. This remarkable correlation 

 extends even to minor or technical botanical characters 

 in the plums. There are two methods in which the 

 plums pack away their leaves in the bud. In some 

 the little leaves are convolute or rolled together, 

 whilst in others they are conduplicate or trough - 

 shaped, one lying inside the other. Now, the two 

 European species which we cultivate, the common 

 plum or Prunus domestica, and the myrobalan or P. 

 cerasifera, have their leaves convolute or rolled in the 

 bud ; and the same thing is . true of the one wild 

 plum of the Pacific coast, and also of the Prunus 

 umbellafa of the extreme south. The Japanese plum, 

 on the other hand, has its leaves conduplicate or 

 folded in the bud, and the same is true of our three 

 native species, the Americana, Wild Goose and Chick- 



