THE ROOT. 



17 



many cases, as in the seedling of Wheat, Flax, etc., 



these may be seen by 

 the unaided eye, appear- 

 ing as a woolly cover- 

 ing. The special office 

 of these is to absorb the 

 dissolved food from the 

 soil. 



8. When aeeed germi- 

 nates, it generally sends 

 a single root (radicle, 



Fig. 3,r.d.) downwards, which is called the primary root. 



This may continue to grow, and remain larger than any 



of its branches or side-roots which 



it sends out, and in this case it is 



called the main, or tap-root. 

 9. The tap-root, when not woody 



(as in shrubs and trees), may be- 

 come fleshy, that is, thickened, as, 



for example, in the Carrot, Turnip, 



etc. This is in consequence of a 



deposit of nourishment which has 



been elaborated or prepared in the 



green parts of the plant. When it 



is larger at the top, or where it joins 



the stem, and tapers gradually down- 

 wards, it is said to be conical (Fig. 



4) ; if it is ttirnip-shaped, that is, 



very large above, tapering abruptly, 



and becoming very slender below, 



Fig. 2. Portion of aroot, with root-hairs, highly mag;nificd. Fig. 3. The Bean in 

 different stages of germination : cai^ cotyledons; //, plumule; r.d., radicle; cau, 

 caulicle ; ivs, leaves. 



2 



