342 LUTHER BURBANK 



cereal is, it by no means takes the place of the 

 others. Wheat, rice, and rye in particular stand 

 unchallenged as the producers of the chief vege- 

 table foods of mankind throughout the civilized 

 world. Oats constitute the most highly prized 

 food for man's chief helper, the horse ; and barley 

 is raised in enormous quantities for purposes of 

 fermentation to produce beverages that retain 

 their popularity generation after generation, 

 whatever may be said as to their unwhole- 

 someness. 



The relatively close relationship of these five 

 grasses is obvious to the most casual observer. 

 Wheat, rye, and barley in particular are so simi- 

 lar that only the practiced eye can distinguish 

 between them with certainty when growing in 

 the field. They are closely related in the eye of 

 the botanist as well, and what may be said of one 

 of them with regard to possibilities of develop- 

 ment applies, with minor modifications, to all. 



They are plants that, having been for ages 

 under cultivation, have developed many varieties. 



But, on the other hand, the varieties that as- 

 sume commercial importance are relatively fixed, 

 owing to the fact that they have always been 

 grown in mass, thus giving no great opportunity 

 for variation, and no necessity for cross-fertiliza- 

 tion. These are the good and sufficient reasons 



