LUTHER BURBANK 



with the hardy plants, I am somewhat handi- 

 capped in the attempt to deal with the more 

 tender ones. 



This is notably true of the orange and its allies 

 of the citrus family. 



These fruits very naturally interested me from 

 the outset, not only because of their economic im- 

 portance, but because the five familiar species of 

 the family, namely the orange, lemon, lime, shad- 

 dock, and citron present inviting diversities of 

 form and habit, and yet are so closely allied that 

 they cross very readily, and thus give the plant 

 experimenter precisely the opening that he is 

 always seeking. 



It is probable that all these citrus fruits sprang 

 from one original species growing somewhere in 

 the region of northern India. 



But although the habitat of these plants has 

 always been restricted to sub-tropical climates, 

 yet they have become so diversified as to form 

 fairly good species, and the different traits of the 

 various members of the clan are fairly fixed. Not, 

 indeed, that any of them may be raised advantage- 

 ously from seed, for here they show the same 

 diversity that is shown by the other orchard fruits. 

 But all varieties of oranges, for example, differ 

 quite radically from any variety of lemons, and 

 the seeds of the orange will not produce the 



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