PLANTS REACT TO LIGHT 227 



the plants extend over the borders in dense flower-beds. Note 

 where the best-foliaged plants are in the greenhouse. Notice 

 the foliage on the outer rows in a very thick cornfield. Ob- 

 serve how plants nearest to buildings reach outward for the 

 light and room. 



Review. — Why is there struggle for existence? How does it affect 

 plants? Tell what it is. How do plants compete for space? What 

 is meant by the phrase "divergence of character?" Give examples. 

 How do plants compete for nutrients and water from the soil? In what 

 respects have plants become modified to the light relation? How do 

 plants grow in dense plantations? On the margins of these planta- 

 tions? You know some tree or other plant: describe how it is consti- 

 tuted to compete with its fellows. 



