A MANUAL OF BOTANY 45 



11. Exercise (A Wkittex Statement) 

 Review topic questions on leaves 



1. What are leaves? Give a good definition in your 

 own words. 



2. What are the functions of leaves ? Name all you know. 



3. Why do leafy plants need sunlight ? 



4. Why do biennials generally produce winter rosettes ? 



5. What do desert plants do to regulate transpiration ? 



6. Why are parasitic flower plants generally devoid of 

 green leaves ? 



7. AVhat advantage, if any, are divided leaves ? 



8. What effect have forests on the moisture of the atmos- 

 phere ? 



9. What are evergreen plants ? 



10. Name three most useful leaf products. 



11. Why do the cacti have their leaves reduced to spines ? 



12. What explanation do you have for a cabbage head ? 



13. Explain the pitcher of the pitcher plant. 



14. Explain, leaf arrangement with reference to light. 



15. Why do leaves wilt ? 



SECTION Vr. THE STUDY OF FLOWERS 

 General Preface to the Special Studies 



General statement. There are many different methods in 

 vogue for the study of flowers, the most common being, per- 

 haps, to study the trillium, tulip, or some other flower of 

 easily discernible parts. 



It has, however, been amply justified in the author's 

 school experience, that a better understanding is to be 

 gained by beginning with such an extremely simple struiv 

 ture as the willow ; for by so doing the student learns tlie 

 subject from the foundation, and appreciates much more 

 certainly that the essential oryans are all that are absolutely 



