50 AGRICULTURE FOR BEGINNERS 



A season of heavy, cold rains during blossoming time 

 may often injure the fruit crop by preventing timely visits 

 from insects. You now also understand why plants often 

 refuse to produce seeds indoors. They cannot, since they 

 are shut in, receive proper insect visits. Plants such as 

 tomatoes or other garden fruits dependent upon insect 

 pollination must, if raised in the greenhouse, be pollinated 

 by hand. 



EXERCISE 



Exclude insect visitors from some flower or flower cluster, e.g. 

 clover, by covering with a paper bag, and see if they can produce seeds 

 that are capable of growing. Compare, as to number and vitality, the 

 seeds of such a flower with those of an uncovered flower. Observe 

 insects closely. Do you ever find pollen on them ? What kinds of 

 insects visit the clover? the cowpea? the sourwood? the flax? Is 

 wheat pollinated by insects or by wind or by some other means? 

 Do bees fly in rainy weather? How will a long rainy season at 

 blossoming time affect the apple crop ? Why ? Should bees be kept 

 in an orchard ? Why ? 



SECTION XVI CROSSES, HYBRIDS, AND CROSS 

 POLLINATION 



In our study of flowers and their pollination we have seen 

 that the seed is usually the descendant of two parents or at 

 least of two organs : one the ovary, producing the seed, the 

 other the pollen, which is necessary to fertilize the ovary. 



It happens that sometimes the pollen of one blossom 

 fertilizes the ovary of its own flower, but more often the 

 pollen from one plant fertilizes the ovary of another plant. 

 This latter method is called cross pollination. As a rule, 

 cross pollination produces a stronger seed, that is, a seed 



