I04 General Botany 



Finally, we must observe that there are in trees all gradations 

 between the deciduous and evergreen habits. In the rainy tropics 

 there are many delicate-leafed evergreens. In the dry tropics 

 the evergreens have thick, fleshy leaves, or they may be quite 

 leafless. Some plants, like the holly and the Virginia creeper, 

 may have the deciduous habit in the North and the evergreen 

 habit in the South. Some deciduous trees, like the cherry, when 

 planted within the tropics become evergreen ; while the magnolia, 

 which is evergreen in the Southern states, becomes deciduous 

 when grown in a colder climate. Evidently leaf habits are in 

 part responses to chmatic conditions, especially to conditions of 

 temperature and moisture. 



PROBLEMS 



1. What are the commonest evergreen trees and shrubs of your locality? 



2. What trees of your vicinity develop leaves earliest in the spring? What trees 



develop their leaves last ? 



3. What trees develop flowers before the leaves? 



4. What trees drop their leaves first in autumn? What trees drop their leaves 



last in autumn ? 



5. What trees shed part of their leaves during the summer? 



6. During how many months does each of these trees carry on food manufacture ? 



7. During how many months do the evergreen trees of your locality manufacture 



food? 



8. For how many months do the three leading crop plants of your locality carry 



on photosynthesis ? 

 9 Do all specimens of the same species of trees put out new leaves at the same 



time? How much variation is there? 

 10. Do those which develop leaves first drop them earliest in the autumn? This 

 information is important in selecting trees for street planting and general 

 landscape effects. 



