* 
THE ROOT. 39 
where there is one, remains and absorbs nutriment from the 
soil. In the true parasite, as Dodder, the original root 
withers and falls away, as soon as the young plant has fixed 
itself to the other. 
117. The root is formed by the growth of the radicle, the 
little conical body which is well seen between the cotyledons 
of many dicotyledonous seeds, as the Pea or Bean. It has 
- a natural tendency to grow downwards, which exerts itself 
in every instance, except perhaps in the Misseltoe, in which 
the radicle always grows in a direction perpendicular to the 
axis of the body on which it may be placed. 
118. The structure of the root is generally similar to that 
of the stem. It is destitute, however, of pores or stomata, 
organs which would be useless on this part of the plant. 
In exogenous plants it presents the bark and medullary rays, 
but no pith. It has no buds, scales, or leaves; or rather its 
buds do not develope as leaves, flowers, or branches, but as_ 
roots ; and it is said to be destitute of spiral vessels. Some — 
eminent vegetable anatomists, however, have discovered spi- 
a several roots ; but they certainly are more rare in the 
root. Underground roots are never green. The root is 
considered to increase in length, only by addition at or very 
near to its extremity—not by the addition of new matter be- 
tween parts already formed. 
119. All parts of the root possess the power of emitting 
rootlets; and hence the primary root divides into many 
branches under ground, in the same manner as the stem does 
in the air. The root is thus enabled to draw more nutritious _ 
matter for the support of the plant, having more absorbing 
mouths or spongioles, and the command of a greater extent 
“many roots descend, and the extent to which they spread, are a 
"eae of i ong rots) are x gd ie Hus 
of soil. One of the principal uses of ploughing is to crumble a 
_ down and divide the masses of earth, and enable the rootlets __ 
‘more easily to penetrate into the soil. The depths to which 
