238 LUTHER BURBANK 



general. And whereas the date palm does not 

 thoroughly perfect its fruit, for the most part, 

 except in regions where the summer is very long 

 and hot, this tree may withstand extremes of 

 temperature that are widely removed from any- 

 thing experienced in the tropics, and other palms 

 generally perfect their fruit wherever they can 

 be grown. 



Indeed, so hardy are some of the palms that 

 the question arises whether it may not be pos- 

 sible by selective breeding and adaptation to 

 develop races of palms that will thrive even in 

 the middle latitudes of the eastern United States, 

 and far to the north of their present limits on 

 the Pacific Coast. The fact that most of the 

 palms now growing in California have been 

 introduced within comparatively recent times, 

 and that they have gradually made their way 

 northward, is suggestive of the possibility of 

 much wider extension of their habitat. 



A difficulty in the attempt to carry out any 

 project in selective breeding calculated to give 

 the palm additional hardiness or any other qual- 

 ity is found primarily in the fact that this tree 

 does not mature its fruit until from ten to 

 twenty-five years of age. But in recent years 

 an effort has been made by the Department of 

 Agriculture and by several private individuals, 



