LUTHER BURBANK 



If this is not absolutely clear, you will do well 

 to re-read the above paragraphs, and it is quite 

 worth your while to consider the matter somewhat 

 attentively. 



If you have only theoretical interest in plant 

 breeding you should be concerned in the matter 

 no less personally, because the same laws of hered- 

 ity that are about to be illustrated apply with full 

 force to all life, including human offspring. 



If, on the other hand, you have thought of un- 

 dertaking some experiments in plant developing, 

 which I hope is the case, it is doubly important 

 that you should get the full significance of these 

 simple formulae. Like other formulae, they are 

 devised solely for convenience in promulgating 

 ideas. As used in the following illustration, they 

 will make it possible to present vividly the case of 

 our black-sheep cherry, and through this to clarify 

 a large number of obscure cases ^that must prove 

 very puzzling to the novitiate in plant develop- 

 ment. 



Explaining the Black Sheep 



Let us now stake our way, as it were, with the 

 aid of the upper-case and lower-case letters, along 

 the line of a series of plant experiments through 

 which a certain patrician cherry was developed. 

 To avoid complications and to escape getting into 

 a tangle of ideas and a maze of letters, let us con- 



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