16 



THE STEM 



scales, and the buds beneath them may be 

 scarcely visible. Thus the "eyes" on an Irish 

 potato are cavities with a bud or buds at the 

 bottom. (Fig. 24.) Sweet potatoes have no 

 evident "eyes" when first dug (but they may 

 develop buds before the next growing season). 

 The Irish potato is a stem; the sweet potato 

 is an enlarged root. 



46. How Stems Elongate. — Roots elongate 

 by growing near the tip. Stems elongate by 

 22. wintergreen, growing more or less throughout the young or 

 showing rootstock. g()ft part or «k etween joints." But any part 



of the stem soon 



reaches a limit be- 

 yond which it cannot 



grow, or becomes 



"fixed;" and the new 



parts beyond elongate 



until they, too, become 



rigid. When a part of the stem once becomes fixed or hard, 

 it never increases in length: 

 that is, the trunk or woody 

 parts never grow longer or 

 jjl j higher; branches do not be- 



' A come farther apart or higher 



from the ground. 



47. The different regions of 

 growth in stems and roots 

 may be observed in seedling 

 plants. Place seeds of radish 

 or cabbage between layers of 

 blotting-paper or thick cloth. 

 Keep them damp and warm. 

 When the stem and root have 

 grown an inch and a half long 



23. Rhizome of a wild sunflower. 



V^pF 



24. Potato. Stems (where?) , fine 

 roots, and rootstocks. 



