16 



THE AMERICAN BOTANIST 



the accompanying illustration. To the ordinary eye, the ray- 

 flowers of this plant are of a uniform yellow color and the disk- 

 flowers are but slightly darker, but when the camera perceives 

 them it tells a different story, for the disk flowers come out 

 quite dark in the print and there is a dusky ring surrounding the 



The dusky ring surrounding the disk. 



disk produced by the base of the rays. It is very apparent, 

 therefore, that what appears to us as a clear yellow flower head 

 is not so to the cam-era and very possibly may not be so to the 

 insect. And having once been shown how easily the eye may 

 be deceived as to flower color how dare we assert with con- 

 fidence, hereafter, that flowers appearing of a certain color to 

 us appear of the same color to insects? 



