The Origin of Species 307 



in other respects were very striking. In height the 

 plants ranged from three to ten feet, and while 

 these variations were due to some extent to the dif- 

 ferences in the soil and moisture, the difference be- 

 tween individuals growing together was sufficiently 

 striking. The flowers showed very great differ- 

 ences in size, in the form of the rays, and in the 

 shade of color, ranging from pure white through 

 various intermediate shades of pink and red to 

 deep crimson. The leaves also varied greatly in 

 size, breadth, and remoteness of their fine divisions. 

 Similar variations might be cited for almost any 

 cultivated species grown in quantity, and to a less 

 degree for most wild ones. 



The gardener by selection can easily control any 

 of these variations, e.g., the color of the flower, and 

 it is probable that natural selection could also take 

 hold of such variations. If, for instance, crimson 

 flowers should be more useful than white ones, it 

 is quite conceivable that the white ones might be 

 eliminated, as the result of natural selection alone. 



The Range of Fluctuating Variations Dependent 

 upon the Nature of the Variation. The limits 

 within which fluctuating variations may act un- 

 doubtedly depend very much on the character of 

 the variation involved. There may, for instance, be 

 physiological reasons which forbid variations in cer- 

 tain directions beyond a given point. Thus, for ex- 

 ample, by selection the percentage of sugar in the 

 roots of sugar beets has been doubled, but it has 



