CHAPTER XVII. 

 THE ROOT. 



FIG. 403. 



EXEECISE LXXI. 

 True Moots and Adventitious Moots. 



WHEN the young plant contained in the seed be- 

 gins to grow, the plumule rises toward the light, 

 while the opposite portion 

 grows downward, and be- 

 comes root. Observe in 

 Figs. 383 and 384 that the 

 root, as it increases in 

 length, sends off branches 

 on all sides. Roots formed 

 thus, by the extension and 

 branching of the root-end 

 of the embryo, are called 

 true roots. 



But, in the sprouting of 

 such seeds as the oat or 

 Indian-corn (Fig. 403, from 

 Prof. Gray), the radicle 

 never lengthens; it be- 

 comes abortive, and the 

 roots spring from the side 

 of the stem. All roots 

 that arise from the sides 

 of stems, either in germi- 

 nation, or at any period in 

 the growth of a plant, are 



