100 THE STORY OF THE PLANTS. 



Now, each primrose plant bears only one form of 

 flower. Therefore, if a bee begins visiting a 

 thrum-eyed form, he will collect pollen on his 

 proboscis at the very base only ; and as long ar 

 he goes on visiting thrum-eyed flowers, he can 

 only collect, without getting rid of any grains on 



FIG. 18. Pin-eyed primrose, 

 cut open so as to show the 

 arrangement of the stamens 

 and stigma. 



FIG. 19. Thrum-eyed prim- 

 rose, cut open so as to 

 show stamens and stigma. 



the deep-set stigmas. But when he flies away to 

 a pin-eyed blossom, the part of his proboscis 

 which collected pollen before will now be op- 

 posite the stigma, and will fertilise it ; while 

 at the same time he will be gathering fresh 

 pollen below, to be rubbed off on the sensitive 

 surface of a short-styled flower in due season. 



