10 THE SMALL GRAINS 



There is, therefore, already considerable development of 

 the embryo plant at maturity of the seed. 



9. Seed. The fruit of a cereal is a caryopsis or kernel, 

 of which the seed and the pericarp are grown together 

 (Fig. 4). In milling, this thin pericarp, together with the 

 adjacent layer of aleurone, is removed as bran (592). In 

 many cases, as in the barleys, the pericarp unites with the 



FIG. 4. Cross-section of a wheat kernel: a, aleurone layer; b, paren- 

 chyma; filled with starch grains ; cd, a portion further enlarged in 

 Fig. 5, showing there the starch grains. 



lemma and palea (84, 113). In other cases (55, 58), the 

 latter are simply close around the kernel and not ad- 

 herent to it, as in the spelt and emmer. 



Near the base of the grain, on the posterior side, there 

 is a mark called the hilum, showing the place of original 

 attachment of the seed to the wall of the ovary. On the 

 opposite side, facing the lemma, is the embryo, showing 

 plainly through the pericarp. An important part of 

 the embryo is the scutellmn, a rather" thick, flat body, 



