LUTHER BURBANK 



hereditary "complexes" that we speak of as unit 

 characters is the most powerful individual factor. 

 But, inasmuch as the great body of antecedent 

 factors are using their influence in unison in 

 another direction, it is inconceivable that the in- 

 fluence of the single new factor should greatly 

 change the aggregate result. 



In this view, what we term a species is a com- 

 pany of organisms in the germ plasm of which the 

 groups of factors for each main characteristic have 

 become purely and unqualifiedly recessive, so that 

 they act as a unit in producing a given character. 

 They thus determine the chief characteristics of 

 heredity in the Darwinian sense, which finds its 

 popular expression in the phrase "like produces 

 like." 



Meantime, there are always minor groups of 

 newer characters that are fighting for recognition, 

 and while these are relatively insignificant because 

 of their newness and small number as compared 

 with the whole, yet they are conspicuous and im- 

 portant in the eyes of the plant developer because 

 they represent precisely those modifications of 

 form and constitution and color that mark what we 

 speak of as variations from type; and because they 

 are so matched against one another in heredity 

 in the manner that we call Mendelian as to make 

 it possible for the plant developer to segregate and 



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