162 THE ELEMENTS OF VEGETABLE HISTOLOGY 



CELL CONTENTS OP BOOTS 



The cell contents of roots are usually stored in 

 the parenchymatic cells. The stored materials may 

 include most, if not all the substances mentioned in 

 the section of cell contents. The most important 

 contents from the histological standpoint are starch, 

 inulin, calcium oxalate crystals and cystoliths. 



FUNCTIONS OF ROOT TISSUES 



The functions of the different structures present 

 in roots may be tabulated as follows: 



Covering tissues. 



Supporting tissues . . . 



' Primary epidermis, 



Cork, 

 ■ Hypodermis. 



Bast fibers, 

 Wood fibers, 

 Stone cells, 

 Endodermis. 



Absorbing tissues Root hairs. 



r Sieve tubes, 

 Conducting tissues. . . \ Ducts, 



I. Medullary rays. 



...,,.,. f Leucoplasts in parenchyma cells, 



Assimilation tissues. . < „ , 



I Parenchyma. 



Storage tissues Parenchyma. 



Meristematic tissues . < _, , . 



I Cambium. 



