28 STARCH. [CH. II 



cells in a honeycomb, and rounded or angular in outline. 

 It is in the cavities of these six-sided cells that the 

 starch grains are stored, and in such quantity that the 

 cells are crammed with them. A few grains are shown in 

 fig. 10. A drawing does not indicate the peculiar bright, 



FIG. 10. 



STARCH GRAINS FROM THE TUBER OP THE POTATO, highly magnified, 

 showing the stratification. 



shining appearance of the grains, but it shows their othei 

 chief feature, namely, their finely striped appearance. The 

 fine lines indicate what is known as the stratification of the 

 grain, that is to say, that it is made up of a set of shells 

 one within the other. The shells are not loose, one from 

 the next, but are rather like the sheets of paper that go 

 to make up cardboard. Stratification is not peculiar to 

 starch, it is an important feature in the structure of 

 cell walls as will appear in a later chapter, where too we 

 shall have to consider the origin and meaning of the 

 stratification. 



I have spoken of the transference of food material 

 from reserve-stores to places where growth is going on 

 and where therefore food is needed. The transference of 

 starch from one part of a plant to another depends on 



