QUESTIONS AND SUGGESTIONS 199 



the rhizome habit of reproduction and its advantages. 7. Describe 

 the sequence of plants on freshly cleared land. 



B. 8. Describe the structure of an Irish potato. 9. Describe 

 potato culture. 10. Describe and explain the appearance of potatoes 

 sprouting in the dark. 



C. n. Describe the structure of an onion bulb. 12. Describe 

 the culture of tulips. 



D. 13. Describe the Indian turnip. 14. Describe the "flower" 

 of the Jack-in-the-pulpit. What cultivated plant has a similar 

 "flower"? 



E. 15. Describe the stools of canna or dahlia. 



Section 49. 1. What is the vernal habit? 2. What plants do 

 you know which have the vernal habit? 3. What are some of the 

 results of the struggle for light in tropical forests ? 4. What are 

 epiphytes ? 5. What plants do you know which are epiphytes but 

 ' are not seed plants ? 6. Assuming that both have the vernal habit, 

 what advantages would a plant coming from a rhizome have over a 

 plant coming from a seed ? 



Section 50. A. 1. Describe the structure of roots, defining epi- 

 dermis, cortex, and stele. 2. Define meristem and cambium. 3. Con- 

 trast stems with roots as to their tropisms. 



B. 4. Define parenchyma. 5. Compare epidermis, cortex, and 

 stele as to complexity. 



C. 6. Contrast xylem and phloem as to functions. 7. Describe 

 the two ways in which vascular bundles are arranged. 



D. 8. Describe the appearance of the cut end of a one-year-old 

 twig. 9. Discuss the changes which occur as the twig grows older. 

 10. Describe bark and its function. 11. Describe the appearance of 

 the cut end of a log. 12. Describe the structure of a vascular bundle, 

 defining pith-rays. 13. Describe the formation of the cambium ring. 

 14. Describe the formation of secondary wood. 15. Describe cork 

 and its production, defining suberin. 16. Explain the furrows and 

 cracks in old bark. Do you know any trees whose old bark is smooth ? 

 If so, how do you explain this fact? 17. Contrast the cylindrical 

 arrangement in perennial stems with that in annual stems. 



E. 18. Describe the scattered arrangement of vascular bundles, 

 giving examples of plants which have it. 19. State the difference 

 between open and closed bundles. 20. State the relation of vascular 



