CHAP. XI STORAGE 63 



XV. If thin slices of the wood of the trunk, branches, and 

 roots of trees be examined under the compound microscope 

 during the resting season (winter) and tested with the proper 

 chemicals, it will be found that considerable quantities of 

 starch are stored away in the pith, medullary rays, and even 

 in the wood cells for use during the season of rapid growth. 



XVI. Of what advantage to the plant are the supplies of 

 nourishment thus stored away? 



XVII. Write a summary of this chapter, stating what 

 plant-parts are used for the purpose of storing food ma- 

 terials, and how they are modified to do so. 



