IMPROVEMENT OF PLANTS 



53 



to point this lesson, especially if a calculation is made of the difference 

 in yield from an acre of each of the two types of plants. 



If any large flowers, like cotton, tobacco, or morning-glory, are 

 blooming, let the pupils carefully remove every stamen from a bud in 

 which the pollen sacks have not yet burst. Tie cloth or paper over 

 the injured flower. Grocers' small paper bags are good. After a 

 number of hours collect pollen from other flowers of the same kind and 

 dust this pollen over the tip of the pistil in the injured flower. Cover 

 it again. In a week or two see whether seeds have formed. 



FIG. 39. RESULTS OF SELECTION m WHEAT, 

 after four years. A, head from sowing small 

 grains; B, head from sowing large grains. 



