THE ECOLOGY OF PLANTS. 457 



5. Describe the chief modes of perennation in herbaceous plants. 



6. Describe the different localities in which plants store up nutriment 

 in one year for their own rapid growth in the next year, and state the 

 nature of the stored substance in the case of each plant that you cite. 



7. What wild flowers have you found growing along the margins of 

 lakes, ponds, and rivers ? Distinguish those which grow with their 

 stems (a) wholly in the air, (&) partly in air and partly in water, (c) 

 wholly submerged. Show by sketches what you mean by the zones of 

 vegetation along the water margin. 



8. Name any plants growing with their leaves wholly submerged. 

 How do such leaves differ from leaves surrounded by air ? 



9. Give the names of four water plants and four marsh plants. 

 Mention all the points you can think of in which water plants differ 

 from land plants. Can you give any explanation of the facts described? 



10. Write a list of any plants which you have found growing with 

 their leaves submerged in water. How do such plants obtain the gases 

 which they require for respiration and photosynthesis? Describe the 

 surface structure of a leaf (a) in a land-plant, (6) in a water-plant. 



11. What special anatomical peculiarities would you expect to find 

 in water-plants ? Explain how the structure you describe is connected 

 with their conditions of life. 



12. Enumerate the more common plants which you have found grow- 

 ing in a marsh. 



13. Write a list of plants which you have found on moorland walks. 

 What peculiarities of leaf-structure have you observed in any six of 

 these ? How does the possession of such peculiarities profit the plant ? 

 What was the nature of the soil on which the moorland plants grew ? 



14. Name all the plants you have found either on a heath or on a 

 moor, distinguishing carefully those which you have only found on 

 heaths or moors. Point out any features which you think fit the plants 

 to live in such situations. 



15. Mention twelve plants you have found growing in company with 

 the Ling (Calluna). Describe the plants on which such plant-associa- 



tions occur, and any general features of heath or moorland vegetation 

 you have observed. 



16. Write an account of the vegetation you might expect to find 

 growing on a swampy moor, and indicate any points in which the 

 plants appear to be structurally adapted to such an environment. 



17. Discuss the ecological conditions that may determine the forma- 

 tion of the " Heather-moor," and give some account of the composition 

 of the flora of each moor. 



