CLASSIFICATION OF AMERICAN WHEAT VARIETIES. 



43 



as ovate. An elliptical kernel outline is one the length of which is 

 more than twice the width and which has sides somewhat curved 

 and both ends rounded. An oval kernel outline is broader, like the 

 ovate, but with both ends of nearly equal width. The three shapes, 

 ovate, elliptical, and oval, are shown in Figure 12, «., b y and c. 

 Modifications of these shapes are indicated by describing kernels as 

 narrowly or broadly elliptical, ovate, or oval, as the case may be. 

 A few varieties, as Baart, show other characteristic shapes, which are 

 given in the descriptions of these varieties. 



Most kernels are classified as ovate, but in a few varieties a consid- 

 erable portion of the kernels may have one or the other of the shapes 

 just noted. The shape of the wheat kernel is influenced by the posi- 

 tion in the spikelet, the position in the spike, and the degree of 

 plumpness. Boshnakian {1ft) has shown that spikelet characters 

 which affect the shape of the wheat ker- 

 nel are mainly: "(1) The stiffness of 

 the glumes, (2) the size and shape of 

 the space in which the grain develops, 

 (3) the number of grains in the spikelet 

 and their position, (4) the density of the 

 head, (5) the pressure caused by the 

 growth of different parts of the head, 

 and (6) the species which produces the 

 kernel." The kernels from the base or 

 tip spikelets on the spike are shorter in 

 proportion to width than the others. 

 The kernels from club wheat or from 

 the tip spikelets of clavate spikes of common wheats are usually 

 laterally compressed or "pinched." Shrunken kernels usually have 

 an elliptical shape because of being narrow. As the width of a 

 kernel of wheat depends largely upon the degree of development of 

 plumpness, this character has very little taxonomic value. 



The tip or brush end of nearly all varieties is rounded, but the 

 kernels of a few varieties, in which the tips are square rather than 

 rounded, as seen from the dorsal view, are described as truncate. 

 Kernels of a few varieties have acute or pointed tips, as seen in both 

 dorsal and lateral views, and such tips are described as acute. 



The shape of the kernel as seen in the lateral view is important in 

 only a few varieties. Many varieties, especially durums and emmers, 

 are more or less keeled on the dorsal surface. Normally the kernels 

 of wheat, in dorso- ventral diameter, are thickest near the base, just 

 above the germ. In a few varieties the kernels are strongly elevated 

 on the dorsal side of this basal portion and then are popularly 

 known as " humped." That term is used in describing such kernels. 



Fig. 12. — Kernel shapes : a, Ovate ; 

 h, elliptical; c, oval. (Natural 

 size and enlarged 3 diameters.) 



