138 FIELD CROPS 



vidual flower or floret is composed of a branched stigma, 

 three anthers, and an outer and inner flowering glume, 

 commonly called the chaff. At the base of each spikelet 

 are two flowerless or empty glumes. At the base of and 

 between the two flowering glumes is a small organ called the 

 lodicule, which, when the stigma is ready to be fertilized, 

 absorbs water, swells, and forces open the glumes. Figure 

 43 shows a spikelet and a flower of the wheat plant. 



Wheat is almost always close-fertilized; that is, each 

 ovary is fertilized by the pollen from the same flower. The 

 anthers are so arranged that the pollen is deposited on the 

 receptive stigma as the anthers are being pushed up out of 

 the glumes by the lengthening of the filaments. It is prob- 

 ably very rarely that any cross-fertilization takes place. 

 On this account, wheat varieties are very stable in character, 

 for it is much easier to keep close-fertilized plants pure than 

 open-fertilized ones like corn and rye. 



The fruit at maturity is in the form of an oblong berry 

 with a longitudinal crease or furrow in one side. This is 

 known as the kernel. The kernels naturally vary in size, 

 color, weight, and composition with the different varieties of 

 wheat and with climatic and soil conditions. 



175. Classification and Varieties. Wheat may be classi- 

 fied in many different ways; as winter and spring wheat, as 

 hard and soft wheat, as bread and durum or macaroni wheat, 

 or by the botanical differences in the varieties. Wheat is 

 commonly divided into eight classes or types; but as only 

 four of these classes are of importance in the United States, 

 only these four will be discussed. 



In the first class, Triticum sativum vulgare, is found all 

 of the common bread wheats, including the hard and soft 

 winter and the fife and bluestem types. This is by far the 



