CHAPTER III 

 WHEAT 



WHEAT, rye, and barley are included in that tribe of the 

 grass order called Horde se, in which the 1- to oo -flowered 

 spikelets are sessile and alternate on the rachis, thus form- 

 ing a true spike. Wheat and rye are still more definitely 

 located in the sub-tribe Triticese, whose genera have the 

 spikelets situated transversely to the rachis and not in 

 the median line. The glumes are o^psite. 



29. Description. In the genus Triticum, including 

 common wheat, the spikes have a terminal spikelet, and 

 the lowest 1-4 spikelets are smaller than the others. 

 The spikelets are closely imbricated ; glumes broad, with 

 one to many awns or a blunt or toothed apex; lemmas 

 rounded on the back, often boat shaped, many nerved, 

 ending in one to several teeth or an awn ; kernels very 

 slightly compressed laterally, deeply sulcate, hairy at the 

 apex, free ; embryo with epiblast. 



There are two sections of the genus, one including the 

 old genus ^Egilops, in which the glumes are flat or rounded 

 on the back, and the other, in which the glumes are sharply 

 keeled, including the cultivated varieties. There are 

 twelve species of J^gilops, distributed in southern Europe 

 and western Asia. Common wheat has long ago been 

 successfully crossed with A. ovata (Hackel, 1890, pp. 170- 

 180), and more recently with A. triticoides. 



30. Roots. On germination, the wheat kernel throws 

 out three seminal roots in the same plane, with occa- 



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