THE DAHLIA 351 



the same time. The outer come to perfection 

 first, and the process of maturing advances to- 

 ward the center of the flower. So the first pol- 

 lenizing must be done just at the right time, and 

 successive pollenizings day by day until the entire 

 flower has come to maturity, if all the pistils are 

 fertilized. 



It is obvious, then, that the crossing of dahlias, 

 while it presents no real difficulties, and is toler- 

 ably sure in its results, is a somewhat tedious and 

 laborious process where the field of operations is 

 wide. But, as already pointed out, it is not neces- 

 sary for the experimenter who is seeking merely 

 to modify existing varieties to resort to hand- 

 pollenizing. 



The varieties that will appear among any 

 ordinary lot of seedlings will afford him ample 

 opportunity for selection. 



On the other hand, the experimenter who 

 wishes to develop new types of striking individ- 

 uality will of course crossbreed the old ones, 

 using species or varieties as widely separated as 

 possible. My own experiments, as already 

 pointed out, have involved the use of wild species 

 from Mexico, and the influence of these wild 

 crosses has undoubtedly been felt in the rather 

 striking results attained in working with a race 

 of flowers that, despite its comparatively recent 



