66 



STRUCTURAL BOTANY. 



CHAPTER XIV. 



THE BOOT, OR DESCENDING AXIS. 



197. The Root is the basis of the plant, and the principal 

 organ of nutrition. It originates with the radicle of the seed, 

 the tendency of its growth is downward, and it is generally im- 

 mersed in the soil. Its office is twofold; viz., to support the 

 plant in its position, and to imbibe from the soil the food neces- 

 sary to the growth of the plant. 



235 



238 



233, White Clover an axial root (with minute tnbers). 234, Buttercups fibrous roots, inaxial. 235, 

 Erigenia root tuberous. 



198. The leading propensity of the root is to divide itself; and 

 its only normal appendages are branches, branchlets, fibres, and 

 fibrillaB, which are multiplied to an indefinite extent, correspond- 

 ing with the multiplication of the leaves, twigs, &c., above. 

 This at once insures a firm hold upon the earth, and brings a 

 large absorbing surface in contact with the moist soil. 



199. The summit of the root, or that place where the root 



