UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 622 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
February 2, 1918 
THE IDENTIFICATION OF VARIETIES OF BARLEY. 
By Harry V. Harlan, Agronomist in Clwxge 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 12 
Page. 
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 satisf}^ 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 
14681°— 18— Bull. 622 1 
