RIDDLES IN FLOWERS 



207 



the solution of all these floral riddles. The insect 

 explained it all. The bright colors and fra- 

 grance were intended to attract him, and the 

 nectar to reward him, and while thus sipping he 

 conveyed the pollen to the stigma and fertilized 

 the flower. 



But now Sprengel himself was met with most 

 discouraging opposition to his theory, showing 

 that he had guessed but half the secret after all. 

 Flowers by the hundreds were brought to his 

 notice, like that shown in Diagram C, in which 



the insect could not transfer the pollen from 

 anther to stigma, as the stigma is closed when 

 the pollen is ripe, and like that in Diagram D, 

 which does not open until the pollen is shed. 

 For seventy years this astonishing fact puzzled 

 the world, and was at last solved by the great 

 Darwin, who showed that nearly all flowers shun 

 their own pollen, and are so constructed, by thou- 



