THE DAHLIA 347 



improving the flower itself, but also in 

 the attempt to hybridize it with the dahlia 

 proper. 



Selective breeding enlarged the flower to 

 about twice its original size, making the rays 

 much rounder and fuller, adding extra rays, 

 and in changing the color of the rays from the 

 usual dark purplish crimson to a light crimson 

 approaching scarlet and in a few cases to a pale 

 pink approaching white. The plant itself was 

 also made more compact. 



All these changes were produced by selection 

 and reselection, working constantly toward the 

 new colors desired, and toward increase of the 

 size of flower, and modification of form. 



The species worked with was a Mexican 

 form. There is an aquatic California species 

 with large, brilliant, yellow flowers, closely 

 related to the species known in the East as 

 "pitchforks." 



For two or three generations, these flowers 

 seemed fixed. I could see no change whatever; 

 no tendency to break into new forms. I at- 

 tempted to hybridize the two species of bidens, 

 but did not succeed, so it was necessary to depend 

 upon selection alone. The plants were grown in 

 large quantities. After several years slight 

 variations appeared; and then, as in so many 



