106 LUTHER BURBANK 



Thus, as we have seen, one of the parents of 

 the Paradox walnut was a tree not indigenous to 

 America. But we may recall also that another 

 hybrid walnut, the Royal, which sprang from the 

 union of two indigenous species, the black wal- 

 nut of the eastern United States and the black 

 walnut of California, rivals the Paradox in its 

 capacity for rapid and gigantic growth. 



So it is obvious that we are by no means re- 

 duced to the necessity of making requisition on 

 foreign lands for material with which to develop 

 our new races of quick-growing forest trees. 



But, on the other hand, the plant developer is 

 always willing to take his own where he finds 

 it. So if foreign species can be found that will 

 hybridize advantageously with our native species, 

 they will of course be welcomed. The reader 

 will recall that I have invoked the aid of num- 

 berless exotic fruit trees and vegetables and 

 flower bearers in the course of experiments in 

 plant development. 



In some cases it will be possible to bring the 

 foreign species and acclimate them without 

 hybridization. This has been done with several 

 species of eucalyptus and acacias which have 

 been brought to California from Australia and 

 have proved a wonderful addition to the ranks 

 of our ornamental and timber trees. 



