POLLEN A TION: HE TEROSPOR V. 



355 



about the same level as the stigma of the former. What does this interesting 

 relation of the stamens and pistils in the two different flowers mean ? As the 

 butterfly thrusts its "tongue'' down into the tube of the long-styled flower 



Fig- 452- ,, 



Dichogamous flower of the bluet (Houstonia ccerulea), the long-styled form. 



for the nectar, some of the pollen will be rubbed off and adhere to it. When 

 now the butterfly visits a short-styled flower this pollen will be in the right 

 position to be rubbed off onto the stigma of the short style. The positions of 



Fig. 453- 

 Dichogamous flower of bluet (Houstonia ccerulea), the short-styled form. 



the long stamens and long style are such that a similar cross pollenation will 

 be effected. 



654. Pollenation of the primrose. — In the primroses, of which we have 

 examples growing in conservatories, that blossom during the winter, we 

 have almost identical examples of the beautiful adaptations for cross polle- 

 nation by insects found in the bluet. The general shape of the corolla is 



