14 



A CHAPTER TO STUDY. 



commodate themselves to the necessities of the plant. We find 

 some stems growing entirely underground and storing up nour- 

 ishment for the plant's growth during the next season. These 

 stems are called the Rootstock and are distinguishable from 

 the root by bearing scales, which are not found on roots proper. 

 (Fig. 51.) 



The Tuber is the end of a rootstock that is thickened or 

 enlarged. The enlarged part is possessed of eyes (buds). The 

 common potato is a familiar illustration of tubers. (Fig. 52.) 

 The Corm is a rounded, compact rootstock. (Fig. 53.) 

 The Bulb is a corm mostly made up of fleshy scales. (Fig. 

 S4-) 



FIG. 51. FTG. 52. FIG. 53. FIG. 54. 



The Scape is a leafless peduncle, or the flower-stalk of a 

 plant that has no stem. 



The Root proper grows downward in the ground and bears 

 nothing but rootlets and root-branches. Its principal function 

 in life is to absorb the nourishment from the soil. 



Aerial Roots are produced in the open air and serve the 

 plant by acting as holdfasts, or helping it to climb. 



Parasites intermingle their roots with the roots or stems of 

 other plants and drain from them their sustenance. 



Thorns are modified branches. Their purpose is to guard 

 the plant from animals that would strip it of its stem and 

 bark. 



