ON TIMBER TREES 
Thus, as we have seen, one of the parents of 
the Paradoy walnut was a tree not indigenous to 
America. But we may recall also that another 
hybrid walnut, the Royai, which sprang from the 
union of two indigenous species, the black walnut 
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 
reduced 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, like Moliere, 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 
numberless exotic fruit trees and vegetables and 
flower bearers in the course of my experiments in 
plant development. There is every reason to 
expect that equal advantage will result from the 
utilization of forest trees from, let us say, Siberia 
in one hemisphere and Australia in the other to 
blend with the strains of American species. 
In some cases it will be possible to bring the 
foreign species and acclimate them without hybrid- 
ization. This has been done with several species 
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