192 Observation of the Origin of Varieties. 



effected nothing more than the isolation of the individ- 

 uals of the new race. 



\Yq have therefore to examine the ''late summer" 

 curves of the 13-rayed, 21 -rayed and double races. Let 

 us begin with the first. 



The extreme limits of the curve of this race at the 

 ])eginning of August were 11 and 21 ray-florets. These 

 numbers gradually decreased until September, when only 

 heads with 13 and 14 rays were formed. In the next 

 year at the end of July the limits were 10-19, but in 

 August 12-14. 



I examined the 21-rayed race, with reference to this 

 character, in the summer of 1898, dealing with the indi- 

 viduals which had been saved for seed. The data for 

 three of the plants^ are summarized in the following 

 table : 



We see that the numbers gradually shift in the direc- 

 tion of the maximum at 21 (in the case of one plant 

 actually reaching it), without any indication of the max- 

 imum at 13 of the other race. The plants dealt with, 

 therefore, clearly belonged to the 21-rayed race. 



^ Over hct periodisch optreden der anomaVicn op monstreuze 

 planten. Kruidkundig Jaarboek, Gent, XI, 1899, PP- 57-58. 



