34 



BULLETIN 1074, U. S. DEPARTMENT OF AGRICULTURE. 



white, indicating a darker glume than those described as white. A 

 few varieties have white or yellowish glumes with brown or black 

 nerves, or the glumes are sometimes tinged on the edges with brown 

 or black. Such varieties are placed in the white-glumed class and 

 the peculiar markings are indicated in the descriptions. The Black- 

 hull variety has glumes which usually are tinged with black, but 

 sometimes are almost entirely black. The Rudy variety has black 

 stripes along the edges of the glumes. 



Glumes of durum varieties classed as yellowish are much darker 

 than those of any of the common wheats classed as white or de- 

 scribed as yellowish white (PI. Ill, Fig. 2, d). This yellowish class, 

 therefore, is quite distinct. It may range in color from a buff to 

 bronze. 



The brown-glumed class usually is still darker than this yellowish 

 class and may vary in shade from light to dark brown and bluish 



brown, and in some varieties there is 

 a reddish or mahogany tinge (PL 

 III, Fig. 2, e, f, and g). For the 

 latter reason most taxonomists have 

 used the term " red," but in the pres- 

 ent work the writers prefer the term 

 : ' brown," as it more accurately de- 

 scribes the glume color of the class 

 as a whole. 



Black-glumed wheats are rare in 

 America. With two exceptions, and 

 these only among the durums (Kahla, 

 PL III, Fig. 2, h) and emmers (Black 

 Winter), there are no commercial 

 varieties having black glumes. The 

 color of the glumes of these varieties 

 varies considerably. Under very dry conditions they may be only 

 faintly tinged and may be more of a blue than a black. 



Fig. S. — Glume length : a, Short ; t, 

 midlong ; c, long. (Natural size and 

 enlarged 3 diameters.) 



LENGTH OF THE GLUMES. 



Glume lengths are described as short, midlong, and long and are 

 used as minor characters in the varietal descriptions. These length 

 differences are illustrated in Figure 3. Usually small-kerneled va- 

 rieties have short glumes and large-kerneled varieties long glumes, 

 but there are exceptions to this. The glumes are usually about three- 

 fourths the length of the lemmas, although in some long-glumed 

 varieties the glumes and lemmas more nearly approach the same 

 length. Polish wheat, Triticum polonicum, has glumes as long or 



