LUTHER BURBANK 



tilized at all if our experimental poUenization 

 should fail. 



Time the Limiting Factor 



But even when restricted to the essentials, the 

 process takes time; and although some thousands 

 of hand-poUenations are done annually in my 

 gardens and orchard, yet, as intimated, we try 

 to leave the bulk of this work to the bees. Of 

 course, these otherwise admirable helpers make 

 no distinction between different varieties of blos- 

 soms, passing freely from one tree to another, 

 regardless of the variety; but they usually confine 

 their attentions on any given day to trees of a 

 single species; that is to say, they do not ordinarily 

 pass from cherry blossoms to the blossoms of the 

 plum or almond, even if all are in season. They 

 seem to prefer not to mix their sweets. So they do 

 not distribute pollen to the wrong flowers as often 

 as might be supposed. 



Where I wish to make poUenizing experiments 

 on a larger scale, I sometimes place a branch of 

 a cherry tree in full bloom among the branches 

 of the tree of another variety, with which I wish 

 to effect hybridization. The bees then transfer 

 the pollen from the borrowed limb to the flowers 

 on the surrounding branches, and a thoroughly 

 satisfactory cross poUenation is often thus brought 

 about, 



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