80 AGRICULTURE ON THE PACIFIC SLOPE 



way for a week or more, putting in fresh ice when 

 needed. What happens to the leaves? This shows 

 us why cold irrigation water should be allowed to stand 

 and become warm in the sun before being used. 



Leaves avoid shading each other. Notice the leaves 

 of English ivy and Japanese ivy. When a leaf is 

 shaded it grows out toward the light, and so the 

 arrangement shown in figures 41 and 42 is brought 

 about. 



Do leaves reach out toward the light? Notice plants 

 which grow in front of a window. Do the leaves turn 

 toward the light? If so, turn the plants halfway 

 around; how long does it take for the leaves to turn 

 back again? Study begonias, nasturtiums, and gera- 

 niums. 



Do branches grow toward the light? Notice trees 

 which are lighted mostly from one side, as trees at the 

 edge of a grove or standing near a house (see figure 43). 



