STRUCTURE OF THE SPIKE 



177 



ORIGIN" AND DESCRIPTION OF BARLEY TYPES 



Origin. In the early history of man barley was a very impor- 

 tant human food, and probably at one time was more important 

 as a bread plant than wheat. It probably had its origin somewhere 

 in western Asia. During the last three centuries it has declined as 

 a human food and is now used mostly as stock feed, and in the 

 manufacture of beer. Its use for the 

 latter purpose is not new, as the ancient 

 Egyptians made it into beer. 



Classification of Barleys. The 

 most common classification of barleys 

 is based on the number of rows of grain 

 on the head and their arrangement (Figs. 

 62 and 63) . There are four main groups 

 as follows : 



1. Six-row Barley (Hordeum hex* 

 aslicJton). 



2. Common Six-row, lateral grains 

 overlapping, sometimes called four row 

 (Hordeum vulgare). 



3. Two-row Barley, slender heads 

 (Hordeum distichum). 



4. Two-row Barley, broad heads 

 (Hordeum zeocriton). 



Structure of the Spike. In the 

 typical barley spike there is a certain 

 similarity. The typical barley spikelet 

 has but one seed with two narrow empty glumes at the base. In the 

 six-row barleys three grains are attached together at the base. Sets 

 of three grains being on opposite sides of the rachis, gives a total 

 of six grains around the spike. 



In two-rowed barley, only the central grain of the three is de- 

 veloped, the two lateral being sterile or only staminate. 



In the true six-row barley the grains are spaced equal distances 

 apart, making six distinct rows of grain (Fig. 62). In the other six- 

 rowed type there are two distinct rows of single grains and two 

 irregular rows, giving a somewhat four-rowed appearance, and this is 



Fia. 63. Difference between zeo- 

 rriton type on left and distichum 

 type, both six- row and two-row, on 

 nght. The zeocriton is distinguished 

 by short joints in rachis, and longei 

 grains. 



