EXERCISE 17. POLLINATION OF PLANTS 



Equipment: A supply of paper bags and a ball of 

 twino. 



Method: («) Go into a corn field when the silks are 

 just beginning to show beyond the husks and tie paper 

 bags over four ears. At the same time tie bags over the 

 tassels of three or four plants. Allow the bag to remain 

 undisturbed over one of the ears for three or four weeks 

 or until the plant is ready to harvest. An examination 

 at this time will show that no grains have developed. 

 Why? 



A week after the first bagging, cut off one of the tassels 

 and dust the pollen on one of the covered ears, removing 

 the bag for the operation and replacing it as soon as the 

 pollination is accomplished. One week later repeat the 

 operation with the other plants. When the corn is ready 

 to harvest remove the bags and examine the ears. 



(6) Plant side by side in the home or school garden 

 a number of hills of yellow and white corn or field and 

 pop corn. In the fall when the corn is husked, note the 

 mixture of two kinds of kernels on the same cob. How 

 did this corn become mixed? 



Discussion: Some flowers produce seeds while others 

 do not. Some ears of corn have vacant places on the cob, 

 or poorly filled tips. From this exercise it will be seen 

 that if a flower is to produce fruit, its pistil must receive 



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