CHAPTER XXIX 



Wheat 



379. Structure of Kernel. The wheat kernel has three 

 distinct coverings (see Fig. 88): (i) The outer cuticle or 

 pericarp which is a hard tough coat, composed largely of 

 ligno-cellulose; this is the seed pod in which the seed is 

 enclosed, and constitutes the main part of the bran. (2) 

 An inner double cuticle of cellular tissue which is called 

 the episperm and consists of two hard coats called respec- 

 tively the inner and outer integument ; this double skin 

 or layer may be considered one coat and forms a part of 



Fig. 88. Structure of wheat kernel : i, Floury portion ; 2, aleurone 



layer; 3, the bran composed of three layers; 4, germ 



(adapted from Bull. 32, Neb. Station). 



the bran. (3) A third, hard, thin skin or layer called the 

 perisperm. The three bran coats constitute about 5 per 

 cent, of the weight of the grain. Within these three 

 bran layers is a single layer of large cells called the 

 aleurone layer. This is sometimes erroneously called the 



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