QUESTIONS ON THE LIGHT-RELATION 51 



and its whole form might be changed. Consider how such a 

 mode of branching would affect any small tree that you 

 know. Every bud has a story to tell of the value of sunlight. 



REVIEW. What is the relation of the plant 

 to sunlight? Does its form ever depend on its 

 relation to light? In what direction do the tops t 

 of plants grow? Where are the most vigorous 

 branches? What is heliotropism? Why are trees 

 sometimes unsymmetrical? Do you know any 

 instances yourself? What is one way in which 

 plants profit by the climbing habit? Explain. 

 Where are leaves borne in reference to light? 

 Where are leaves usually largest? Do they de- 

 velop in darkness? Are leaves borne directly 

 above one another? How may leaves be arranged? 

 Explain what phyllotaxy is. Are leaves always 

 arranged definitely? Explain the arrangement 

 in some plant that is not mentioned in this 

 lesson. What is the "sleep" of leaves? Which 

 surface of the leaf is exposed? What are com- 

 pass plants? How do buds show what the effect 

 of sunlight has been? What buds start first in 37. The big terminal 



spring? buds. Hickory. 



