LUTHER BURBANK 



THE OEIGIN OF THE FITTEST 



(3) As to the origin of the variations observed 

 in nature, which supply the material for the opera- 

 tion of natural selection, Mr. Burbank has very 

 pronounced ideas. He believes that the usual 

 cause of such variation is hybridization between 

 different species or varieties. One of his earliest 

 discoveries was that by crossing divergent races 

 or totally different species he could produce hy- 

 brids that were different from either parent, and 

 that sometimes these hybrids breed true. 



A striking illustration of this was furnished 

 when he cross-pollenized a raspberry brought 

 from Siberia with a California dewberry a 

 species of trailing blackberry. The result was a 

 berry of a new type, differing radically from 

 either parent, which seems entitled to rank as a 

 new species, inasmuch as it has its own type. 



Another illustration of the production of a new 

 species by hybridizing is found in Mr. Burbank 's 

 Phenomenal berry, the product of a union between 

 the Cuthbert raspberry and the California dew- 

 berry. Yet others are the plumcot, already re- 

 ferred to; the extraordinary Paradox walnut, 

 which combines the strains of the Persian walnut 

 and the California black walnut; and the Shasta 

 daisy, combining the strains of a European, an 

 American, and a Japanese species, and itself dif- 

 fering very radically from any one of its an- 

 cestors. 



Mr. Burbank has found many instances of 

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