ON THE WATSONIA 



involving longer and longer rays in the series that 

 developed from yellow through orange to red. 



But an assumption based solely on this 

 plausible analogy would not call for very serious 

 consideration. The real strength of the theory lies 

 in the support given it by the observed relations 

 of the different flower colors when brought 

 together through cross-pollenation of the flowers 

 themselves. 



It is believed, on independent grounds, that 

 the relations of dominance and recessiveness in 

 Mendelian heredity are determined exclusively, or 

 at least in large part, by the newness or oldness, 

 in an evolutionary sense, of the respective ele- 

 ments that make up a pair of Mendelian factors- 

 referring, it should be understood, to the number 

 of repetitions, not to the mere lapse of time. 



If this assumption is correct and there is a 

 large amount of evidence drawn from many fields 

 to support it then a guide is at hand with which 

 to test the theory of color evolution 



Indeed, it is largely through the application of 

 this guide that the theory of color evolution itself 

 has been developed. 



Making a practical application, it would appear 

 that the color green, as manifested in a flower, is 

 so remote an inheritance that it would be recessive 

 to any and every other color; that blue would 



[299] 



