PLANTS AND HOW THEY GEOW 97 



They are not young roots, because they never grow- 

 larger. They are only tiny little hollow tubes which 

 contain sap. They have no pores, or holes for water 

 to enter, but it easily soaks through their thin walls. 

 Thus these root hairs drink in the soil water which 

 contains many of the plant foods; and the sap car- 

 ries this watery food up along the larger roots and 

 stem to the leaves. Here the sunshine helps to make 

 the plant food ready to build up the stem, leaves, 

 and the fruit of the plant. The larger roots do not 

 take plant food from the soil. Their work is to hold 

 the plant firmly in its place in spite of storms and 

 heavy rains. When a plant is taken up to be trans- 

 planted, most of the small rootlets with their many 

 long hairs are broken off. Perhaps you can now 

 understand why a plant is so likely to wilt when it 

 is transplanted. 



The Stem. The stem, or trunk, bears the leaves 

 and holds them up in the air and sunshine. It car- 

 ries the watery plant foods from the roots up 

 through the outer wood layer to the leaves. The 

 materials, or starch and sugar from the leaves, pass 

 down through the bark to the part where they are 

 needed to enlarge the plant. 



The Leaves. But more interesting than roots or 

 stem are the leaves. They serve as so many stom- 

 achs where the.plant food is digested and made 

 ready for use. The chief work of the leaves is to 

 make the plant foods over into starch and sugar. 

 They take a large part of this starch and sugar, 



