LUTHER BURBANK 



ice age; so on mere geographical grounds the spe- 

 cific difference between the Siberian raspberry 

 and the California dewberry might be accepted 

 without further argument. But, quite aside from 

 this, differences between the two forms are suffi- 

 cient to give them independent specific rank in 

 the mind of any botanist. 



The fact that one is classified as a blackberry 

 and the other as a raspberry will sufficiently estab- 

 lish their diversity in the mind of the layman. 



Yet the report from Santa Rosa told of the 

 hybridizing of these diverse forms, and of the 

 production of a new fruit differing very markedly 

 from either parent, although retaining some of the 

 characteristics of each; and told further that this 

 new hybrid, far from being sterile, has such fer- 

 tility that it ripens its main crop of berries long 

 before most kinds of raspberries and blackberries 

 commence to bloom, and continues to bear more 

 or less berries all summer. 



So the evidence that hybrid offspring of two 

 species may be fertile and may thus offer material 

 for the action of natural selection in the creation 

 of new species appeared doubly demonstrative. 



It is probable, then, that the announcement of 

 the development of the Primus Berry would have 

 aroused no small measure of interest among prac- 

 tical plant breeders and theoretical students of 



[182] 



