PLANT BREEDING 41 



great value, not to the plant in its struggle with 

 the ordinary natural forces, but to man, by con- 

 serving and guiding its life forces to supply him 

 with food, clothing, and innumerable other 

 luxuries and necessities. Plant life is so com- 

 mon that one rarely stops to think how utterly 

 dependent we are upon the quiet, but magnifi- 

 cently powerful work which is being constantly 

 performed for us. 



It was once thought that plants varied within 

 the so-called species but very little, and that true 

 species never varied. We have more lately dis- 

 covered that no two plants are ever exactly alike, 

 each one having its own individuality, and that 

 new varieties having endowments of priceless 

 value, and even distinct new fixed botanical 

 species can be produced by the plant breeder, 

 often with almost the same precision that ma- 

 chinery for locomotion and other useful purposes 

 are produced by the mechanic. 



The evolution and variation of plants are 

 simply the means which they employ, as species, 

 in adjusting themselves to external conditions. 

 Each plant must adapt itself to environment 

 with as little demand upon its forces as possible 

 and still keep up in the race. The best endowed 

 species and individuals win the prize, and by 

 variation as well as persistence. The constantly 



