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MORE ABOUT STARTING NEW PLANTS 



light wood in the spring, and usually of darker wood in 

 the summer and fall, is formed by the cambium, so that 

 the age of a tree can easily be determined, when cut 

 down, by counting these pairs of rings. 



b. The stem of the cornstalk consists of a series of nodes, 

 or swellings, which are separated by internodes. Each 

 internode is made up of a hard outer rind, or bark, and a 

 soft interior structure composed of numerous hollow fibers 



and pith. The fibers 

 are thread-like and are 

 embedded separately in 

 the pith. They corre- 

 spond rather closely to 

 our blood vessels, in 

 that they are the bearers 

 of the sap of the plant. 

 They run upward in 

 each internode, leaving 

 the stem at the nodes to 

 enter the leaves. 



126. Roots have much 



the same structure as 

 The three dark spots are open breathing gtems> They ftre less 



firm, however, and they 



have one important feature that stems do not have. This 

 is the growth of hair that densely clothes new roots. 



These hairs are each about a fourth of an inch long and 

 as fine as the threads of a spider web. They grow out of 

 surface cells on the roots. They are very delicate, and are 

 easily destroyed. Without them a plant cannot grow, for 

 it is through them that food enters the plant in solution 

 in the soil water. In transplanting plants, special care 

 must be taken not to pull off or destroy too many of these 

 root hairs. 



