40 BULLETIN 1074, U. S. DEPARTMENT OF AGRICULTURE. 
LENGTH OF THE KERNEL. 
The length of the kernel is used here as a major character in dis- 
tinguishing varieties of common and club wheat. 
Koernicke and Werner (133), in their descriptions of wheat varie- 
ties, indicated the average length and width of the kernels in milli- 
meters and the average number of kernels in 10 grams. The kernels 
were described as very small, small, large, and long. Heuzé (772) 
described the kernels as short, medium, or long. The size of the 
kernels of any variety varies slightly when grown in different sec- 
tions or in different years in the same section. From necessity, there- 
fore, the limits of the classes in which varieties are placed must be 
overlapping. A kernel of wheat reaches its 
maximum length several days before ripen- 
ing. The length, therefore, is fairly con- 
stant, even when it isconsiderably shrunken. 
and. is the most valuahle of the kernel dimen- 
sions for taxonomic purposes. In mak- 
ing measurements only the normal kernels 
should be used. The kernels from the tip 
spikelets on a spike and from the upper 
florets in the spikelet are below normal in 
Fig. 10.—Kernel lengths: a length. 
Short; b, midlong: c, long. In the keys two classes are made, namely. 
(Natural size and enlarged 3 kernels short to midlong and kernels mid- 
diameters.) 3 : 
long to long. In the descriptions three 
classes—short, midlong, and long—sometimes are mentioned sepa- 
rately. These kernel lengths are shown in Figure 10. 
The short to midlong class includes varieties whose kernels meas- 
ure within the limits of 4 to 7.5 mm. in length. The midlong to long 
class includes varieties whose kernels come within the limits of 6.5 
to 10 mm. For individual samples more definite limitation is pos- 
sible. For this purpose the term “short” is used for kernels varying 
from 4 to 6 mm. in length; “ midlong” for those varying from 6 to 8 
mm., and “long” for those varying from 8 to 10 mm. These latter 
measurements are considered as minor characters and are occasionally 
used in descriptions either alone or usually following the adjective. 
The measurements, enlarged ten times, are illustrated in Figure 11. 
TEXTURE OF THE KERNEL. 
The texture of wheat kernels is an important character in classi- 
fication. It has an economic value in America, as most wheat is mar- 
keted in commercial classes, which are fixed largely on a basis of 
texture, because hard wheats generally are better for milling and 
bread making than soft wheats. 
