48 THE BOOK OF USEFUL PLANTS 



each leaf. When the dry winds rob the soil of 

 moisture, the roots go deeper. The leaves roll 

 their edges inward and sometimes overlap, in order 

 to reduce the amount of surface exposed to sun and 

 wind. The pores are thus closed to save the 

 water supply. When rains come, the normal con- 

 ditions are restored, and food-making becomes the 

 chief business of the plant. Notice how the corn- 

 husks, even, spread out into leaves, to do their 

 share of this work while their bases protect the ear. 

 Even the stalk is green, and able to join in the 

 labors of the leaves. 



How is it that the corn plant can carry so much 

 sail, and yet not have its leaves whipped into 

 strings by the winds? Test for yourselves the 

 flexibility and strength of the midrib of a leaf, 

 the fibres in the leaf margins, and in the tubular 

 leaf base that sheathes the stalk. Notice the 

 frilling of the leaf blade, especially near its joining 

 with the sheath. Swing the whole leaf as far as 

 possible, to find out what amount of play the leaf 

 sheath allows by its own flexibility. What part 

 of a circle is this play? Now hold the sheath 

 tightly against the stalk, and find out the use of 

 the frilling of the leaf blade. Pull the tip to left 

 or right until the frill is straight. Reverse the 

 direction, until the opposite frill is taken up. 



