THE STRUCTURE OF STEMS. 



213 



The plant is again shown in Fig. 384 (Gray), after 

 the production of two internodes and two pairs of 

 leaves. The stem still ends with a bud, and the root 



FIG. 388. 



FIG. 384 



has undergone further development. Now, what in- 

 ternal changes have accompanied these external ones ? 

 Cells have elongated into fibres, or united into 

 ducts, and, if we examine a thin section of a young 

 stem, we may observe the way in which these ele- 

 ments are arranged. Whether we take our section 

 from a sprouting maple, which would represent the 

 woody plants of temperate regions, or from a sprout- 



