502 Mutations 



The fact that the origination of such forms 

 is accessible to direct investigation is proven 

 quite independently of all further considera- 

 tions. The new variety came into existence at 

 once. The leap may have been made by the 

 ancestor of the year 1895, or by the plant of 

 1899, which showed the first central rays, or 

 the sport may have been gradually built up dur- 

 ing those four years. In each case there was a 

 leap, contrasting with the view which clahns a 

 very long succession of years for the develop- 

 ment of every new character. 



Having discovered this first trace of doubling, 

 it was to be expected that the new variety would 

 be at once as pure and as rich as other double 

 composites usually are. Some effect of the 

 crossing with the other seed-bearing individuals 

 might still disturb this uniformity in the follow- 

 ing year, but another year's work would elim- 

 inate even this source of impurity. 



These two years have given the expected re- 

 sult. The average number of the rays, which 

 had already arisen from 13 to 34 now at once 

 came up to 47 and 55, the last figure being the 

 sum of 21 and 34 and therefore the probable 

 uttermost limit to be reached before absolute 

 doubling. The maximum numbers came as high 

 as 100 in 1900, and reached even 200 in 1901. 

 Such heads are as completely double as are the 



