86 LUTHER BURBANK 



which involved but a slight modification of the 

 molecular structure of the flower, inasmuch as 

 the light waves that produce blue lie next to the 

 green on one side in the spectrum. 



The subsequent modifications of color were 

 made in two directions progressively. 



Some flowers were modified in the direction 

 of the violet end of the spectrum, and others in 

 the direction of the red end of the spectrum. 

 The former were first light blue, then deep blue 

 and indigo — represented among existing plants, 

 let us say, by the larkspur and gentian— and 

 ultimately violet. Flowers modified in the other 

 direction were at first yellow, then orange, and 

 finally red. 



Evidence is lacking to answer the question as 

 to which end of the spectrum was reached first — 

 that is to say, whether the flowers of violet color 

 or red were first evolved. But possibly the two 

 may have been developed somewhat contempo- 

 raneously, and they would thus take their place 

 in the hereditary scale more or less on an 

 equality. 



In any event, we may be fairly assured that 

 there were blue flowers and yellow ones, and 

 probably also indigo-colored flowers and orange 

 ones in existence before there were flowers of 

 pure violet or of deep red. 



