LUTHER BURBANK 



ise than a large individual nut from a tree that 

 in general bore small nuts. 



A "PAPER-SHELLED" WALNUT 



As to the possibility of rapidly developing a 

 new variety of nut through selection from the 

 product of a single tree of unusual quality, Mr. 

 Burbank 's experience in the production of the 

 Santa Eosa paper-shelled walnut is illuminative. 



The tree from which this valuable variety was 

 developed was a Persian walnut of unknown ante- 

 cedents, that grew on a San Francisco street. Mr. 

 Burbank noted that this tree bore many nuts that 

 had exceedingly thin shells, and even some nuts 

 that had shells that did not altogether cover the 

 kernel of the nut, suggesting in this regard the 

 partially stoneless plum with which his experi- 

 ments in the development of a race of stoneless 

 plums had been undertaken. 



Growing a large number of seedlings from nuts 

 of this unusual tree, and selecting among them for 

 different qualities, Mr. Burbank had presently a 

 colony of English walnuts, some of which pro- 

 duced nuts so devoid of shell covering that the 

 birds discovered their lack of armament and de- 

 stroyed the kernels by pecking at them. The en- 

 tire lack of shell proving thus a detriment, it was 

 necessary to conduct the further experiments in 

 selective breeding in the opposite direction, thick- 

 ening the shell rather than eliminating it. But 

 material for these experiments was at hand, and 



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