IIORDEUM 141 



The embryo of barley is very similar to that of wheat. 

 It occupies but a small part of the grain. Five to eight 

 secondary rootlets occur. The epiblast is absent in the genus 

 Hordeum. ' The endosperm varies from mealy to glassy or 

 translucent. Mealiness is the result of a high percentage of 

 starch, while translucency indicates a high percentage of 

 protein. The relative amounts of starch and protein in the 

 different types vary. The two-rowed barleys are used almost 

 exclusively in brewing. 



There is no gluten in barley grains, and for this reason 

 light bread cannot be made from the flour. 



Color of Grain. — Harlan has made a study of the color of 

 barley grains. He says: "There are two coloring materials 

 in barley: One, anthocyanin, is red in its acid and blue in 

 its alkaline condition; the other, a melanin-like compound, 

 is black. The pigments may occur in the hulls, the peri- 

 carp, the aleurone layer, and occasionally in the starch endo- 

 sperm. The resulting colors of the grain are quite compli- 

 cated. White denotes the absence of all pigment; a heavy 

 deposit of the melanin-like compound in the hulls results in 

 black; a light deposit, brown. Anthocyanin in the hulls re- 

 sults in a light violet-red. In naked forms the melanin- 

 like compound in the pericarp results in a black kernel; 

 anthocyanin produces a violet one. The acid condition of 

 anthocyanin in the pericarp superimposed upon the alkaline 

 condition in the aleurone layer gives the effect of a purple 

 color, while a blue aleurone beneath a colorless pericarp is 

 blue-gray. White hulls over a blue aleurone cause the grain 

 to appear bluish or bluish gray. Black hulls over a blue 

 aleurone give, of course, a black appearance. The antho- 

 cyanin is always violet in the hulls and in the pericarp, show- 

 ing that these tissues are in an acid condition, and always blue 

 in the aleurone layer, showing an alkaline condition. The 



