GRAIN OF WHEAT 



65 



nel contains most of the oil, the oil content depends largely upon 

 the size of the embryo. (Fig. 68.) Sometimes, however, much 

 of the starch of the endosperm is replaced by sugar, as in case 

 of Sweet Corn, which is much used as a vegetable on account of 

 its soft sweet endosperm. 



Grain of Wheat. — In structure, a grain of Wheat is similar to 

 a kernel of Corn. In the section through a Wheat grain, shown 

 in Figure 69, though the parts are not labelled, they can be deter- 

 mined by referring to the section of the Corn kernel shown in 



Fig. 68. — Kernels of Corn 

 with high and with low per- 

 centage of oil. A, kernel with 

 large embryo and hence rich 

 in oil. B, kernel with small 

 embryo and low percentage of 

 oil. C and D, face views of 

 two kernels differing in size of 

 embryos and therefore in oil 

 content, e, embryo. After 

 Bulletin 87, University of Illi- 

 nois Agricultural Experiment 

 Station. 



Fig. 69. — Lengthwise section 

 through a Wheat kernel. The 

 embryo is to be compared with 

 the embryo of the Corn kernel 

 {Fig. 66) and parts labelled. 



Figure 66. In milling i a grain of Wheat, a number of special 

 products are obtained. The woody pericarp and seed coat 

 with the aleuron layer and some of the outermost starch cells 

 constitute the bran. When bran is finely ground, it is known as 

 shorts. Middlings differ from shorts only in containing a larger 

 percentage of starchy endosperm. In making the best grades of 

 flour, only the starchy endosperm is used and the quality of the 



1 On Bread. Bulletin 4, Ohio Agricultural College. Bread and Bread 

 Making. Farmers' Bulletin 389, U. S. Dept. of Agriculture. 



