CHAPTER XII 

 PLANTS AND HOW THEY GROW 



Learning about Plants. Since men and animals 

 live largely on plants, and farmers are kept busy 

 growing crops to feed the world, we want to know 

 more about how plants grow and produce seed. We 

 may easily see what the animals about us eat and 

 drink, but it is not so easy to learn just how plants 

 eat and grow and bear frnit. 



Dividing Their Work. Plants need food, water, 

 and air, just as animals do. They also need warmth 

 and light. The plant has different parts — a stem, 

 roots, leaves, and flowers. It divides its work up 

 among these parts. The roots of the plants have 

 their work, and it is different from that of the stem 

 and leaves. 



Roots and Their Work. Let us first look at the 

 roots. Pull up a radish from the garden, and you 

 notice that the upper part of the root is large and 

 round and is stored full of food. Below is a tap 

 root which grows smaller and smaller to the end 

 several inches down. All along this tap root are 

 tiny rootlets with root hairs branching off from 

 them. These root hairs cover only the tips of the 

 smallest rootlets, but they extend out in all direc- 

 tions. They are very close together, for often there 

 are as many as thirty thousand on one square inch. 



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