GBNBBAL MORPHOLOGY OF THE PLANT 17 



ditions, its embryo begins at once to develop, the radiole growing 

 in a downward direction, while the plumule extends itself up- 

 wards. We thus can distinguish between the two parts of the 

 axis according to the direction of their growth. From the 

 lower portion is formed the root system, from the upper portion 

 the shoot, consisting of the stem and its appendages. 



Section I. — The Eoot. 



The root is seen thus to be the descending axis of the plant. 



It usually attaches the plant to the suh stratum on which it 



grows and absorbs nutriment therefrom. It presents certain 



features which distinguish it at once from the stem ; we have 



FiGf. IS. 



Fig. 18. LongitudiDal section of the apex of a root of Buckwheat, a. Grow- 

 ing point, h. Root-cap. 



seen, though it may branch repeatedly it only bears such 

 appendages as are like itself ; it never bears true reproductive 

 organs, and only under exceptional circumstances does it give 

 rise to leafy shoots or leaves. It has also other peculiarities of 

 structure ; its growth takes place by increase of its substance 

 immediately behind its apex, so that the growing part (a, fig. 18) 

 VOL. I. c 



