34 
BULLETIN 1074, U. S. DEPAETMEXT OF AGRICLTLTUEE. 
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, /, and g). For the 
latter reason most taxonomists have 
used the term " red," but in the pres- 
ent work the writei^ prefer the term 
•' brown,-' as it more accurately de- 
scribes the glimae color of the class 
as a whole. 
Black-glumed wheats are rare in 
America. With two exceptions, and 
these only among the durums (Kahla, 
PI. Ill, Fig. 2, A) 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. 3. — Glume length : a. Short ; 6, 
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 gliunes 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 polmiicu??i, has glumes as long or 
