498 Mutations 



suit showed that no further selection could be 

 of any avail, and that I had succeeded in purify- 

 ing the 21-rayed grandifiorum variety. 



It is from this grandifiorum that I have finally 

 produced my double variety. In the year 1896 

 I selected from among the above quoted 1500 

 plants, 500 with terminal heads bearing 21 or 

 more rays. On these I counted the rays of all 

 the secondary heads about the middle of August 

 (1896) and found that they had, as a rule, 

 retrograded to lower figures. On many thou- 

 sands of heads only two were found having 22 

 rays. All others had the average number of 21 

 or even less. I isolated the individual which 

 bore these two heads, allowed them to be fertil- 

 ized by insects with the pollen of some of the 

 best plants of the same group, but destroyed the 

 remainder. 



This single exceptional plant has been the 

 starting point of my double variety. It was not 

 remarkable for its terminal head, which exhib- 

 ited the average number of rays of the 21-rayed 

 race. Nor was it distinguished by the average 

 figure for all its heads. It was only selected 

 because it was the one plant which had some 

 secondary heads with one ray more than all the 

 others. This indication was very slight, and 

 could not have been detected save by the 

 counting of the rays of thousands of heads. 



