84 INTRODUCTION TO BOTANY 



5. Would you expect to find any kind of compass plants in wood- 

 lands? Why? 



6. Why do most aquatic flowering plants have leaves that are ex- 

 posed to the air, rather than submerged leaves ? 



7. Why are trees of the moist tropical regions usually evergreen ? 



8. May a shrub or a tree be deciduous or evergreen, according to 

 circumstances? Give examples. 



9. If you wanted to make a cactus plant produce leaves, how would 

 you treat it? Why? 



10. If an aquatic plant were transplanted into desert soil and an 

 extreme xerophyte into a shady swamp, what appearances would in 

 each case soon show that the plant was dying? 



11. What mesophytes do you know that can grow under a very wide 

 range of conditions as regards light and moisture? Compare, with 

 regard to their tolerance of drought, some common plants important in 

 agriculture. 



