212 THE ELEMENTS OF VEGETABLE HISTOLOGY 

 CELL CONTENTS OF SEEDS 



The cell contents of seeds are contained within 

 the parenchyma of the endosperm. These contents 

 are exceedingly varied and may include starch, aleu- 

 rone, fixed oils, volatile oils, alkaloids and glucosides. 

 Aleurone usually occurs in seeds containing fixed oil; 

 but starch is rarely, if ever, present in seeds contain- 

 ing these substances. 



FUNCTIONS OF SEED TISSUES 



The functions of the different structures present 

 in seeds may be summarized as follows : 



„ ( Epidermis, 



Covenng tissues ( stone cells. 



~ ,. f Stone cells, 



Supporting tissues { „., , 



yy . I Fibers (ran 



,-,... f Parenchyma, 



Storage tissues < 



Fibers (rarely). 



Parenchyma, 

 Collenchyma. 



