96 



LABORATORY EXERCISES 



EXERCISE 90 

 STUDY OF LEAVES 



Apparatus and Materials. Different kinds of leaves, 2-quart and 

 1 -quart glass fruit jars, bottle, marble, dilute hydrochloric acid, pan 

 and pail of water, parsley or spinach, test tube, pine splinter. 



a. Get together at least 15 kinds of leaves in addition to 

 those on the seedlings of Exercise 88. Get leaves of trees and 

 weeds as well as of garden plants; be sure to know the name 

 of the plant to which each leaf belongs. Include in your list, 

 if possible, the leaf of the apple tree, of red and white clover, 

 of the maple, and of the black locust. 



Study 309, of the text, for some of the differences between 

 leaves. Do any of the leaves you have brought have stipules? 

 Have all of them petioles? Which leaves are deeply indented? 

 Which ones are compound, that is, broken into leaflets? What 

 is the kind of veining in each leaf? 



Have you found any plants with tendrils? If possible, get 

 a leaf of Boston ivy and some of the suckers by which it clings. 



b. Classify the facts learned in a under the following heads: 



c. The Work of Leaves. Half fill a 2-quart fruit jar with 

 water, and hold over the mouth of it a bottle in which you are 

 generating carbon dioxide from marble and dilute hydro- 



