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PASTORAL AND AGRICULTURAL BOTANY 



embryo. A groove, or furrow, is found along the side of the grain facing 

 the palet. In cross section, the following cell layers are distinguishable 

 (i) ovary wall, or pericarp, several cells thick; (2) testa, two layers of 

 cells; (3) tegmen; (4) aleurone layer often called the gluten layer; (5) 

 starchy endosperm; (6) embryo. The bran layer includes the three outer 

 layers viz., pericarp, testa and tegmen. The latter is represented by a 



FIG. 72. Heads of varieties of spring wheat grown at the Moro substation: A, 

 Little Club; B, Pacific Bluestem; C, Karun. (After Stephens, David E.: Experiments 

 with Spring Cereals at the Eastern Oregon Dry-Farming Substation, Moro, Oregon. Bull. 

 498, U. S. Department of Agriculture, 1917, p. 19.) 



single layer of cells outside of the aleurone layer. In the undeveloped 

 embryo, this tissue was large and prominent. The protein in the wheat 

 varies from 8.1 per cent, to 17.2 per cent, with an average of 11.9 per cent, 

 and there appear to be five kinds of wheat proteins: globulin, albumin, 

 proteose, gliadin and glutenin, according to the researches of Osborne 

 and Vorrhees. There are two kinds of wheat, hard and soft. The hard 



