LUTHER BURBANK 



Then, too, there is a time element involved. 



Species that are closely similar in appearance 

 are those that have branched from the ancestral 

 stem in relatively recent epochs; species more 

 distinct trace their cousinship through remoter 

 lines ; and forms so widely diverse as to be placed 

 in different orders have been separated for still 

 longer periods. And we must suppose that in 

 each generation the new forms have taken on a 

 modicum of new traits, and have tended to fix 

 the divergence of earlier traits through which they 

 attained specific difference. 



In due course, then, it comes to pass, that a 

 given form has branched so widely from its 

 cousins that the harmony of purpose, so to speak, 

 that once obtained between them no longer 

 obtains. 



The racial memory as to their common 

 ancestry has become blurred, if the phrase be 

 permitted, and each species has become so fixed 

 in its own manner of life that no compromise 

 between them would be possible. 



And so we find, in point of fact, that it becomes 

 increasingly difficult to hybridize species that are 

 obviously widely divergent in form of stem and 

 foliage and flower, and that in a vast nimiber of 

 instances any attempt to hybridize these forms is 

 altogether futile. 



[42] 



