ARTIFICIAL SELECTION 



97 



Leaving Biirbank's other fruit and berry creations un- 

 noticed, we may refer to his curious cross-bred wahiut results 

 (Fig. 03), the most astonishing of which is a liybrid Ijctween 



H 



1 



Fig. 63. — At left, leaf of English walnut, JiKjlnns regia; at right California Mack 

 walnut, Jiujlans californica; and in the middle a leaf of the hybrid Paradox, first 

 generation. (From photograph by Burbank.) 



Juglans Californica (staminate parent) and J. nigra (])istillate 

 parent), which grows with an amazing vigor and ra})icHty, the 

 trees increasing in size at least twice as fast as the combined 

 growth of both parents, and the clean-cut, glossy, bright green 



