HORDEUM 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 alkaHne condition; the other, a melanin-Hke 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 Ught 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 



