36 



BULLETIN 1074, U. S. DEPARTMENT OF AGRICULTURE. 



WIDTH OF THE SHOCLDEB. 



The shoulder widths often differ from the glume widths. For this 

 reason they are described separately, but on the same basis of meas- 

 urement and by the use of the same terms, narrow, midwide, and 

 wide (Fig. 5). 



SHAPE OF THE SHOULDER. 



Shoulder shapes are described in overlapping terms which allow 

 for a considerable variation, which is nearly always present in the 



same spike. The terms used are want- 

 ing, oblique, rounded, square, elevated, 

 and apiculate. These shapes are shown 

 in Figure 6. 



BEAK CHARACTERS. 



The word " beak " is used here for 

 the short projection which terminates 

 the keel of the glume. In some varie- 

 ties it aproaches an awn in appearance. 

 Scofield {173) first used the term beak, 

 previous authors having referred to it 

 as a tooth or point. The beaks vary in 

 width, shape, and length. These char- 

 acters are of considerable minor im- 

 portance in identification and are used in the descriptions of the 

 varieties. 



Fig. 5. — Shoulder widths : a, Nar- 

 row ; b, midwide ; c, wide. (Nat- 

 ural size and enlarged 3 diame- 

 ters.) 



Fig. 6. — Shoulder shapes : a, Wanting ; o, oblique ; c, rounded ; d, square ; e, 

 elevated; f, apiculate. (Natural size and enlarged 3 diameters.) 



WIDTH OF THE BEAK. 



Beak widths are described as narrow, midwide, and wide (Fig. 7). 

 The average beak is only about 1 mm. wide, so the variations are very 



