FARM CROPS. 141 



having the same type of head. Generally speaking, 

 the spike of American grown wheat will average about 

 three and one-half inches in length and contain an 

 average of forty kernels. 



The Grain. A wheat grain is a one-called, dry 

 fruit with a thin ripened ovary growing together with 

 the seed, so that the seed and pod form a single body. 

 The fruit of wheat is called a caryopsis. In shape the 

 wheat kernel is about twice as long as broad, slightly 

 flattened in its longest dimension, and with a crease or 

 furrow extending laterally on the side opposite the em- 

 bryo. The grain contains a relatively small embryo, 

 and a very large development of endosperm. 



Bessey * gives the structure of a wheat grain as con- 

 sisting of the (i) ovary wall or pericarp, the (2) 

 outer and (3) inner integument, the (4) nucellus, 

 which portions are usually grouped together under the 

 common name of bran, the (5) aleurone cells also 

 called the gluten cells, and the (6) starch cells. 



The United States Department of Agriculture gives 

 as the average analysis of wheat : 



Water 10.5% Fat 2.1% 



Crude Fiber 1.8% Protein 11.9% 



Ash 1.8% Nitrogen Free Extract. . .71.9% 



Unlike oats, wheat when ground has a property, 

 common only with rye, of forming a sticky dough when 

 mixed wit;h water. This is due to the gluten con- 

 tained in the grain, which gives to wheat when mixed 

 with yeast its value for making light bread. 



Wheat Position. Wheat stands third of the 

 great cereals in the United States in number of bushels 

 produced. In value of crop, however, it stands sec- 

 ond. In 1909 the total yield of wheat in the United 

 States as given by the Bureau of Statistics of the 

 United States Department of Agriculture, was 737,- 

 189,000 bushels, which was slightly more than twenty 

 per cent, of the total crop of the world. The average 



* Bulletin No. 32, Nebraska Experiment Station. 



