62 THE ROOT. 



country. Thus, the cocoa, and the cashew-nut, and the seeds of the mahogany, 

 have been known to perform long voyages, without injury to their vitality. Squir- 

 rels, laying up their winter stores in the earth, birds, migrating from clime to 

 clime, and from island to island, in like manner conspire to effect the same im- 

 portant end. 



CHAPTER X. 



THE EOOT. 



136. THE ROOT is the basis of the plant, and the principal 

 source of its nourishment. It originates with the radicle of the 

 seed ; the tendency of its growth is downwards, and it is gener- 

 ally immersed in the soil. 



a. When the radicle has burst the integuments of the seed, and penetrated the 

 soil, its body becomes divided into branches, or fibres; each of these is again 

 divided and sub-divided into fibres, often exceedingly numerous and minute, ever 

 extending and multiplying, until ,the vegetable has attained its full growth. 



137. The prone direction of the root is accounted for by the extreme delicacy 

 of the fibres, which renders them averse to the air and light, by (heir avidity for 

 moisture, and by the effects of gravitation. 



a. Although the primary direction of the roots is do wr ward, they are not 

 known to extend to any great depth. After having descended to a certain dis- 

 tance beneath the surface, they extend themselves hoi i /ontally, keeping at about a 

 uniform depth, however great the irregularities of t ne surface. 



138. The number and extent of the roo* must always correspond to the 

 demands of the vegetable, both for affordiim it nourishment, and for maintaining 

 it in its erect position. It follows, the efore, that for every expanding leaf, or 

 extending twig, there must be a cor esponding increment of the roots and fibres 

 beneath the soil. 



139. Roots are generally distinguished from stems by their 

 downward direction, by the presence of absorbing fibres, by the 

 constantly irregular arrangement of their branches, ano^ by the 

 absence of buds, stomata, and pith. 



140. To all these characteristics there are, however, exceptions. Thus, buds, in 

 peculiar circumstances, are developed by the roots, sending up shoots, or suckers, 

 around the parent stem. This does not happen in the natural or healthy state 

 of the plant, but only when the life of the upper axis is partially or wholly 

 destroyed, the roots remaining in full vigor, and elaborating more nourishment 



