CHAPTER XI 



ROOTS 



1. The first root arises as we saw in our germinated 

 seeds as an extension of the radicle. In nearly all trees 

 and shrubs and in many herbs, this grows on as a strong 

 main root, pushing its way downwards, and giving 

 off branches which at first grow nearly horizontally 

 (showing that they are dia-geo-tropic) and themselves 

 branch again in all directions. These smaller branches 

 grow out in any direction, without reference to gravity, 

 but only towards dampness. The root branches start 

 always from the youngest parts, so that those nearer 

 the ends are younger and shorter than those further 

 back, as may be seen very well on the seedling of a 

 Broad-bean grown in a glass bottle. 



When the first root grows on strongly like this, it 

 is often termed a tap-root. 



But in many plants (for instance with the com- 

 mon Bean) the end of the main root soon dies and 

 its place is taken by a large number of smaller roots 

 which arise at the base of the hypocotyl, and branch- 

 ing out in all directions, are of much the same size 

 and importance. These are termed fibrous. Most 



