THE FERTILIZATION OF FLOWERS 199 



doubtless see that a good deal of the pollen had been left 

 upon these. 



You certainly should be now in a position to understand 

 what is constantly happening in all strawberry beds. The 

 bees are busily at work carrying pollen from blossom to 

 blossom, and thus causing the fertilization of the little 

 ovules and their development into seed. This growth of 

 the seed upon the surface of the future berry causes the 

 parts beneath the seeds also to develop into the luscious 

 fruit. 



You can easily prove that this development of the berry 

 will not take place unless the seeds are fertilized by the 

 pollen. For if you cut off the upper part of the pistils 

 upon one side of the berry as the petals are unfolding, so 

 as to remove the stigmas, and then watch what happens, 

 you will be likely to find that one side of the berry which 

 is left to be fertilized by the bees will develop and that the 

 other side will not develop. You will thus have been the 

 cause of forming an abnormal berry of very little value, 

 but I hope you will have proved to yourself that the bees, 

 which are thus making possible our crops of strawberries, 

 are farm friends, without which we should fare badly. 



CROSS-FERTILIZED FLOWERS 



It is evident that in the case of the squashes and cucum- 

 bers, as well as of the strawberries, the pollen that occurs 

 upon the stigmas of a seed-bearing flower must come 

 from another flower. When pollen is thus carried from 

 one flower to another, the blossom is said to be cross- 

 pollenized and the ovules as a result are cross-fertilised ; 

 that is, the ovules are fertilized by pollen from another 

 blossom which is usually upon another plant. When a 

 flower is pollenized and fertilized by the pollen from its 



