CLASSIFICATION OF AMERICAN WHEAT VAKIETIES. 
37 
small, and general observation is the only basis for describing them. 
Those that are wider than the average are called wide, and those that 
are narrower are called narrow. 
SHAPE OF THE BEAK. 
The apex of the beak varies considerably in shape. It is described 
as obtuse, acute, and acuminate. Obtuse beaks are blunt at the apex. 
Fig. 7. — Beak widths : a. Narrow ; 
h, midwide ; c, wide. (Natural 
size and enlarged 3 diameters.) 
Fig. 8. — Beak shapes : a. Obtuse ; l, 
acute ; o, acuminate. (Natural size 
and enlarged 3 diameters.) 
Acute beaks come to a point at the apex. Acuminate beaks are nar- 
rowly and very sharply pointed. All awnecl spikes have acuminate 
beaks. These shapes are shown in Figure 8. 
LENGTH OF THE BEAK. 
Beak lengths are quite variable, especially in the awned varieties, 
and are considerably influenced by environment. In general, condi- 
tions which increase or decrease the 
length of the beak affect nearly all 
varieties to a similar degree. In the 
awnless wheats the differences in 
length are not great, but in many va- 
rieties they are quite distinct. The 
length of the beak is measured from 
the shoulder of the glume upward. 
On most awned wheats the length 
increases from the base of the spike 
to its apex. The range of differ- 
ence varies greatly with the variety. 
For this reason no definite measurements are used in describing the 
lengths, but instead the average maximum and minimum lengths are 
recorded in millimeters. None of the awnless varieties here de- 
FlG. 
9. — Beak lengths, showing seven 
variations. (Natural size.) 
