PLANT LIFE AND PLANT USES 



INTRODUCTION 



PART I PLANTS AND OURSELVES 



i. Our Dependence upon Plants. Plants are a part 

 of life. Without them all life, our own included, would 

 soon come to an end. Our lives depend upon their lives. 



You are very much interested in life, but the impor- 

 tance of plants as a part of it may not have occurred to 

 you. You know that food is one of the necessities of life, 

 but you may not know that all food, directly or indirectly, 

 comes from plants. You know that the country in summer 

 is covered with plants. You know that their leaves hide 

 the soil and make the hills and valleys green. But you 

 may not know that green leaves are the food factories of the 

 world. 



When you eat an apple you are eating food that comes 

 from a plant directly. When you eat an egg you are eat- 

 ing food that comes from plants indirectly. The hen which 

 laid the egg lived on plants and on small animals which 

 got their food from plants. All food comes thus from 

 plants. Other living things can change foods from one kind 

 to another, but only plants can change substances which arc 

 not food into substances which are food. 



It is not for food alone that our lives depend upon the 

 lives of plants. There are many other things which make 

 them important to us. In this study you are to learn of 



