198 STEMS 



recent years this insect has caused immense damage to 

 trees in the eastern United States. Many thousands of 

 dollars have been spent in efforts to exterminate it. In 

 combating this and other insect enemies of plant life the 

 best general method which has been found is to encourage 

 in every way the abundance of birds and of other insects 

 which prey upon those which do the principal damage. 



QUESTIONS AND SUGGESTIONS 



SECTION 46. i . What appears to be the principal function of stems ? 

 Compare them with roots as to principal function. 2. Make a 

 summary of your previous knowledge of the structure of stems. 



SECTION 47. i. What are various ways in which aerial stems 

 may be classified ? 2. What are herbaceous stems ? Give examples. 

 3. Give examples of shrubs. 



A. 4. Describe the arrangement of the branches of some common 

 plant with an erect stem. 5. What are the two types of structure 

 of erect stems ? 6. What is mechanical tissue ? Give an example of 

 it. 7. What is the crown of a tree ? What are the two principal 

 types of crowns ? 8. What advantages have hollow stems over 

 solid stems ? 9. What advantage have solid stems over hollow ones ? 



B. 10. What appears to be a principal reason for the existence 

 of so many kinds of plants? n. Discuss the advantages and dis- 

 advantages of prostrate stems. 



C. 12. Describe the growth of vines in a tropical forest. 13. What 

 is a liana ? Give an example. 14. What are the three ways by 

 means of which plants climb ? Give examples of each. 



D. 15. What are cladophylls ? Give examples. 16. Name plants 

 whose thorns are like stems in their origin. 



SECTION 48. i. Define rhizomes and give examples. 2. Define 

 tuber, bulb, and corm. 



A. 3. Describe the habit of growth of the May apple. 4. What 

 garden plants have rhizomes ? Do such plants require attention 

 after their growth has once been established? 5. Will fertilizer 

 placed on an asparagus bed in the fall cause it to produce better 

 shoots the following spring? Explain your answer. 6. Describe 



