2 BULLETIN 622^ JJ. S. DEPAETMEXT OF AGRICULTURE. 
done much to stimulate interest in barley. At the same time a demand 
for more detailed information on all our crops has developed. Plant 
problems, especially studies in variations and inheritance, are being 
persistently attacked. T\Tien this new interest was directed toward 
barley, it immediately became apparent that this crop, because of 
the unusual clearness of the varietal distinctions, was exceptionally 
well suited both to student instruction and to genetic studies. This 
clearness comes in part from the very broad limits of the gi'oup. 
The variable characters are numerous and the separations sharp. 
Few cultiA'ated crops present such contrasts as hulled and naked 
kernels,^ awned and hooded lemmas, fertile and infertile lateral 
florets, etc. The number of factors, coupled with the fact that all 
forms are perfectly fertile when crossed with each other, has resulted 
in a large number of easily distinguished varieties. The relative 
ease of subdividing the species makes the crop a profitable one to the 
student, and the definiteness of its varieties makes it equally useful 
to the plant breeder. 
The lack of available literature and the confusion existing as to 
the identity of the various forms have been a real handicap to stu- 
dents and plant breeders alike. Studies in crop plants must include 
a comprehensive summary of the forms and types of each crop. This 
is a necessity for that familiarity with the crop which both student 
and agronomist should possess and is essential to a proper under- 
standing of the publications of others dealing with the subject. 
At present American literature contains no such summary. In- 
deed, the only work in English which attempts to present a complete 
arrangement of the forms is Beaven's "Variety of Barley" (1902). ^ 
This is out of print and is to be found in very few libraries. In 
French there are the works of Heuze (1872, 1896-97), and in Ger- 
man those of Kornicke and Werner (1885), Voss (1885), and Atter- 
berg (1899). The utilization of these and other more fragmentary 
publications is difficult. Frequently they are not available, and even 
if at the disposal of the investigator they present as many different 
methods of treatment as there are authors. In some instances the 
departures are so revolutionary that serious confusion has resulted. 
The aims of this paper are (1) to coordinate the various schemes 
of classification and to reconcile them as far as possible, (2) to make 
available the work that has already been published on barley and 
to suggest modifications to obtain a more logical arrangement of the 
varieties, (3) to add the several new forms of barley wliich have been 
^ The word kernel is used throughout this publication to indicate the naked kernel 
(caryopsis) in the naked varieties and the kernel with lemma and palet attached 
(caryocist) in the hulled vai-ieties. It was found too cunxbereome to use the more limited 
terms, as they required repeated explanations. 
- For complete citations, see " Literature cited," p. 31. 
