Pollination: or How to Cross Plants 273 



the pollen and the stigma must receive it. In Fig. 80, the 

 stamens are shown at E. In the flower A, which has just 



FIG. 83. Flower of night-blooming cereus. 



expanded, these stamens are rigid and in condition to 

 shed the pollen, but in the flower B, they have shed the 

 pollen and have collapsed. The stigma in this case is 



