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 then* 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 KOOT. 



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 gTowth 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 

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

 extending and multiphdng, until the vegetable has attained its full gi'owth. 



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

 of the fibres, Avliich renders them averse to the air and light, by their avidity for 

 moisture, and by the effects of graAdtation. 



a. Although the primaiy direction of the roots is downward, they are not 

 knoAvn to extend to any great depth. After ha-\dng descended to a certain dis- 

 tance beneath the surface, they extend themselves horizontally, keeping at about a 

 unifonn depth, hoAvever great the in-egularities of the surface. 



138. The number and extent of the roots must always con-espond to the 

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

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

 extending tAvig, there must be a corresponding 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 hregular arrangement of their branches, and by the 

 absence of buds, stomata, and pith. 



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

 peculiar cncumstances, 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 



