PLANTS. 



69 



Cells from Potato Tuber. 

 (Showing Starch, Grains.) 



which are filled with liquid or solid matter. The cells 

 of a potato contain little grains of starch, floating in 

 a watery liquid. As the potato ripens, these grains 

 become larger. When a ripe potato is boiled, the starch 

 grains swell so as to burst 

 the cells, and give the pota- 

 to a " mealy " appearance. 

 Starch is obtained from 

 potatoes by grinding to 

 break the cells, and then 

 washing out the starch. 



Growth consists in the 

 multiplication of these 

 cells, either by dividing 

 the old cell into several 

 new ones, or by forming 

 several new cells upon the outside of the old one. 



In the lower orders of plants there are some that con- 

 sist of single cells, each new cell forming a separate 

 plant. Others are composed of a number of these sim- 

 ple cells loosely attached to each other. 



The mushroom that grows in a single night, ordinary 

 mold, and the blight or smut that sometimes forms 

 upon corn and grain, are examples of plants entirely 

 composed of these simple, loose cells. 



In the higher orders of plants, ripe fruit and some 

 other soft, succulent parts, are also composed of simple 

 cells, so loosely connected as to be easily separated from 

 one another. 



In the more substantial parts of most plants, however, 

 the cells are not so soft and loose, but are firmly con- 

 nected together, forming what is called vegetable tissue. 



Cells are of different shapes in the different varieties 



