UNITED STATES DEPARTMENT OF AGRICULTURE 



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BULLETIN No. 622 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



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Washington, D. C. 



PROFESSIONAL PAPER 



February 2, 1918 



THE IDENTIFICATION OF VARIETIES OF BARLEY. 



By Harry V. Harlan, Agronomist in Charge of Barley Investigations, Office of Cereal 



Investigations. 



CONTENTS. 



Varieties of Barley 1 



Review of the literature 3 



Variable factors in cultivated barley 5 



Fertility 6 



Adherence of the flowering glume 6 



Outer glumes 6 



Terminal appendages of the lemma 7 



Color 7 



Density 8 



Scheme of classification 8 



The species of cultivated barley 10 



Key to the species 1 12 



Scheme of classification — Continued. 



Key to the varieties 14 



Key to the subvarieties 16 



Rejected species, subspecies, and varieties 22 



Lines for further study 25 



Identification of thrashed material 26 



Varieties grown in field culture in the United 



States 28 



Key to commercial varieties 28 



Summary 30 



Literature cited 31 



VARIETIES OF BARLEY. 



This bulletin has been prepared primarily to meet a widespread de- 

 mand for a publication on the forms of barley. Although advantage 

 has been taken of the opportunity to call attention to a number of new 

 forms, the main object has been to satisfy the demand from experiment- 

 station workers and advanced students in agronomy for an outline 

 of the cultivated barleys. This demand can be traced to three 

 causes — the many new forms of barley annually added to our collec- 

 tions, the broadening field of genetic and agronomic studies, and the 

 confusion in and lack of availability of the literature on the forms of 

 barley. 



The increase in the number of barley varieties has been rapid. Not 

 only have many new sorts been produced by the various agricultural 

 experiment stations, but there has been a large number of importations. 

 These importations have been of many types and of themselves have 



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