THE WHEAT PLANT 13 



The starchy interior is eighty per cent or more 

 of the weight of the kernel. Viewed under the 

 microscope, it is shown to contain cells filled with 

 starch grains. The cell walls are cellulose. Be- 

 sides starch, which is the principal material in 

 the cells of the endosperm, are protein, some oils, 

 and a little sugar. The term gluten, so often 

 used, is not a single substance. It includes two 

 or more kinds of the protein. The gluten is 

 important in wheat since it gives baking qualities 

 to flour. 



Germ. - The germ is a miniature plant ready 

 to grow when it is planted. It is very appropri- 

 ately called the embryo. This part of the seed is 

 connected with the endosperm, from which it 

 draws food supplies during germination. When 

 man uses the grain for food he changes all this 

 provision of nature. The food materials in the 

 embryo are principally fats or oils, although there 

 is also protein, sugar, and starch. 



By weight, ten per cent or more of the wheat 

 grain is water, though the amount varies greatly. 

 There is also some ash in each part of the grain. 



The Kinds of Wheat. - The various kinds of 

 wheat represent to some extent the natural in- 

 fluences of the countries in which they have grown 

 so long. Yet they have been greatly modified by 

 man during recent years. The State Agricultural 

 Colleges and Experiment Stations have by careful 



