THIRD GRADE SPRING WORK 179 



Note the relation of the strong and the weak branches to 

 the sunlight that they receive. Where is the best fruit found 

 on a tree? Why? 



LESSON LIII 

 PLANTS NEED MOISTURE 



When do we have the most rain? What influence has this 

 upon wild vegetation ? Where is wild vegetation more abun- 



EFFECT OF MOISTURE UPON GROWTH OF TREES 



The trees in this row were all planted at the same time, in soil that is sandy and uniform. 

 They are irrigated by a small stream running from left to right. Most of the water soaks 

 in before the last trees are reached; the growth is in proportion to the moisture received. 



dant, on the hill, or in the valleys? Account for this. Why 

 do irrigating ditches so soon become clogged with vegetation ? 

 Give many illustrations of the effects of much moisture and 

 of little moisture. Deprive a plant of water for a short time, 

 and note the result. Show the difference in size between a 

 plant grown with plenty of water and another of the same 

 kind grown with too little. 



