308 FIELD -CROPS FOB THE COTTON-BELT 



small grains possess considerable power of adapting them- 

 selves to their environment. As a rule, the oiore favorable 

 the conditions are for growth and the thinner the seeding is, 

 the greater is the tendency to tiller. However, very thin 

 seeding with the idea of inducing 

 tillering is not advisable, as it will 

 usually result in decreased yield. 



378. Leaves. — The wheat leaf 

 (Fig. 49) consists of four principal 

 parts: (1) the blade, or that part of 

 the leaf which hangs free from the 

 stem; (2) the sheath, constituting 

 that part which envelops^ the stem 

 tightly; (3) the ligule, a thin mem- 

 brane growing at the juncture of the 

 blade and sheath and also clasping 

 the culm; (4) the leaf-auricle, being 

 a thin outgrowth from the base of 

 the blade. In the case of wheat, 

 small hairs are produced on the edges 

 of the leaf-auricles whereas the auri- 

 cles of, barley and rye are hairless. 

 Oats usually produce no auricles. The leaf-blade of wheat 

 is usually narrower than that of either barley or oats. 



379. The spike (Fig. 50). — The inflorescence of wheat 

 is arranged in a long, narrow, compact cluster at the sum- 

 mit of the stem and is called the " spike " or "head." That 

 part of the stem running through the spike, to which the 

 flower-stems are attached, is called the "rachis." The 

 short joints of the rachis are put together in such a way as 

 to give it a zigzag appearance. The spikelets are produced 

 at these joints on alternate sides of the rachis. The length 

 of the wheat spike varies from 2J^ to i}^ inches, the av- 



FiG. 49. — A wheat leaf, 

 showing 1, blade; 2, 

 sheath; 3, ligule; and 

 4, auricle. 



