328 LUTHER BURBANK 



and produce fertile offspring are not entitled to 

 rank as species, even in the modified view of the 

 meaning of the word species that the evolution- 

 ary doctrine has introduced. 



Yet after all there is a certain tangibility 

 about the idea connoted by the word species that 

 the practical classifier cannot ignore. The black- 

 berry and the raspberry, for example, are so 

 obviously different in many really essential parts 

 of their structure that to deny them specific indi- 

 viduality would be to introduce an element of 

 iconoclasm that would shake the entire structure 

 of systematic botany. 



So when evidence is presented that a black- 

 berry and a raspberry have been combined, and 

 that the offspring is a plant quite as fertile as 

 either of its parents, though markedly different 

 from both, the case seems to give evidence that 

 the offspring of true species are not necessarily 

 sterile. 



And the fact that the new hybrid differs so 

 widely from either parent that it would be 

 named by the classifier as constituting a new 

 species according to ordinary standards, and that 

 it breeds true to its new form, seems to furnish 

 further evidence that new species of plant life 

 may conceivably arise by the hybridization of old 

 species. 



