2 BULLETIN 137, U. S. DEPARTMENT OE AGEICULTUEE. 
In America there are no native stocks. The grain-producing areas 
are relatively new. The varieties peculiar to a section are usually 
the result of chance introductions. Breeding material from foreign 
sources is as likely to contain desirable types as is that already at 
hand. In this investigation, in order to obtain the proper basis upon 
which to conduct breeding work, stocks were assembled not only 
from local sources but from all over the world. Many distinct 
strains were isolated from each stock, for both the local varieties and 
the foreign introductions were usually either races that had not been 
purified or that had become mixed after purification. The isolation 
was accomplished by head and plant selections, which when grown 
in pedigree rows formed a surprisingly large collection. When to 
these were added a still greater number from the progeny of hybrids, 
the problem became one of elimination. The plant selections from 
their very nature were made more or less arbitrarily, and hundreds 
of these forms were necessarily duplicates. These duplicates, espe- 
cially as long as they were not so recognized, were a drain upon the 
breeder, and it was soon realized that the efficiency of a nursery was 
measured, not by the number of stocks it carried but by the number 
it eliminated. 
It was to accomplish this reduction better that the character 
studies were made. The distinctions found were of two classes, 
morphological and physiological. The morphological variations 
were, in the broader divisions, of taxonomic value, and many of 
them were practically invariable. The physiological characters 
were, from their nature, more difficult to appraise. They were found 
to possess not only more widely fluctuating limits, but the limits 
often overlapped and at times the characters became inseparable. 
In physiological characters a further distinction was made between 
permanent and place variations. Some separations were so wide 
that they never became confusing, while others became evident only 
when grown under certain conditions of soil and climate. Such dis- 
tinctions are worthless as taxonomic features, but have proved very 
valuable as indications of individual qualities in breeding. Even the 
lack of stability in a character does not destroy its usefulness, as 
the tendency of a strain to behave in a certain manner under certain 
conditions may mark an inherent difference. 
It is realized that distinctions of this kind are only a part of plant 
breeding, and it is not thought that that part is clarified in any 
great measure. In this paper are given a few of the observations 
that have been found useful in barley breeding, and with them many 
that have been found useless. The data upon which the conclusions 
are based consist of some 200,000 recorded observations, extending 
over a period of five seasons and embracing experiments at St. Paul, 
Minn. ; Williston and Dickinson, N. Dak. ; Highmore, S. Dak. ; Moc- 
