POLLIXA TION: HE TEROSPOR Y. 



355 



about the same level as tlie stigma of the former. What doi-s this interesting 

 relation of the stamens and pistils in the two different flowers mean ? A^ 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 riglit 

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



Fig. 453. 

 Dichogamous flower of bluet (Houstonia cceruleal, tlie short-styled form. 



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

 be effected. 



654. Pollination 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 polli- 

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



