DISTINCTIONS IN CULTIVATED BARLEYS. 3 
casin, Mont.; Aberdeen and Gooding, Idaho; and Chico, Cal. Of 
the work done at these points, that at St. Paul, Minn., which was 
conducted in cooperation with the State experiment station, was the 
most extensive. 
REVIEW OF THE LITERATURE. 
Although the literature of barley is, with the possible exception 
of wheat, more extensive than that of any other cereal crop, the pub- 
lications bearing directly upon the theme of this paper are com- 
paratively few. The great mass of the European publications, 
especially the German ones, have to do with the malting quality of 
barley. They are concerned mostly with its chemical constituents, 
the effect of soil, climate, and culture upon the nature and composi- 
tion of the grain, and the behavior of the converting enzyms in 
grains of different character. The same is true of papers on the 
morphology of the grain, and even many of the publications treating 
directly of barley breeding have little bearing upon the present dis- 
cussion, as they are often concerned only with the correlation of 
characters or with the behavior of hybrids. It is only the papers 
dealing with the taxonomic features of barley, and experiments such 
as those of the Swedish Plant-Breeding Association at Svalof, 
which have had for their end the isolation of plant variants, that are 
of particular pertinence. 
The first comprehensive systematic work was that of Kornicke 
(15) 1 , who described 44 botanical forms of barley, using spikelet 
fertility, color, nature of the awn and glume, and the adherence or 
nonadherence of the palea. His groups will undoubtedly form the 
bases of all future classifications. The classification of Yoss (25) is 
important largely because he based a part of it upon the extent of 
overlapping of the grains, thus forecasting in an indefinite way the 
use of density. Atterberg (2) made use of the bristle and nerve 
characters discovered by Neergaard, mentioned below, and subdi- 
vided the previous groups until he had 188 named botanical varieties. 
Beaven (3), by a rearrangement and compilation of previous classi- 
fications and by growing and describing a large number of hybrids 
of Karl Hansen, Kornicke, and others, gave a very clear conception 
of the entire species. His work is perhaps most valuable in the 
placing of the Abyssinian forms with abortive lateral florets in a 
group by themselves. He does not make use of the finer subdivisions 
employed by Atterberg. Kegel (21) , on the contrary, carries the sub- 
division still farther and uses twisting of the spike and earliness and 
lateness of the variety in his separations. The last, a purely physio- 
logical phase, he employs in named botanical forms. 
A review of the work at Svalof is especially valuable in this con- 
nection because of the fact that a large part of that effort has been 
1 The figures in parentheses refer to the bibliography at the end of the bulletin. 
