46 



BULLETIN 1074, U. S. DEPARTMENT OF AGRICULTURE. 



Fig. 16. — Cheek shapes : a, Rounded ; ~b, angu- 

 lar. (Natural size and enlarged 3 diame- 

 ters.) 



CHEEK CHARACTERS. 



The cheeks of a kernel are the ridges along each side of the crease 

 on the ventral surface of the kernel. The most distinguishing 

 character of the cheek is the outline of the crest in cross section. 

 This is described as rounded or angular. These shapes and some of 

 the variations that exist in each are shown in Figure 16. Extremely 



starchy (yellow-berry) ker- 

 nels always have rounded 

 cheeks, while the cheeks of 

 shrunken kernels are always 

 angular. It is necessary, 

 therefore, to examine nor- 

 mally developed kernels in 

 order to recognize the differ- 

 ences. All of the durum wheats have angular cheeks. Most of the 

 common wheats have cheeks which are more or less angular, but a 

 few varieties, such as China and Turkey, consistently have rounded 

 cheeks. There is no sharp distinction between the angular and 

 the rounded cheeks. 



BRUSH CHARACTERS. 



The brush of the kernel is the hair at the tip or the end opposite 

 the germ. Cobb (71) described in detail the brush of 50 varieties of 

 wheat grown in Australia. 



SIZE OF THE BRUSH. 



The size of brush refers to the area which it occupies on the 

 kernel. The area of the brush is described as small, midsized, and 

 large. These differences are shown 

 in Figure IT, a, b, and c. A small 

 brush is one which occupies only 

 a portion of the tip of the kernel. 

 In kernels which are distinctly 

 pointed at the tip, however, it may 

 cover all of the end, but because 

 of the small area occupied it is 

 still referred to as small. A mid- 

 sized brush covers the tip of the 

 kernel. Nearly all varieties of 

 wheat come within this class. A 

 large brush is one which extends 

 partly over the sides of the kernel, chiefly along the crease. 



a 



Fig. 17. — Brush sizes : a, Small ; &, mid- 

 sized ; c, large ; d, collared crush. (Nat- 

 ural size and enlarged 3 diameters.) 



LENGTH OF THE BRUSH. 



The length of brush refers to the average length of hairs, which 

 are described as short, midlong, and long. These lengths are shown 



