96 
W. C. Etheridge 
The review and discussion of the work of others has shown that a clas- 
sification of varieties of oats, in order to be effective, must be based on 
the morphology of the plant. Accordingly the present classification 
has proceeded by the following steps: (1) a study of the morphology of 
the plant in order to discover the various characters by which individual 
varieties may differ; (2) an analysis of the varieties en masse, to reach 
the types which for the present purpose are considered elemental, that 
is, types that differ in one or more morphological characteristics; (3) an 
arrangement of varieties in groups, regardless of nomenclature, according 
to their likeness to the elemental types that represent the groups. Finally, 
the groups have been fully described and named, and a key has been con- 
structed for their identification. 
The system of naming the groups has consisted merely in applying 
the name that occurred the most frequently among the specimens of each 
group. This system, while arbitrary, seems the only logical one, for in 
many cases there is no means of determining which of several names was 
carried by the original variety. In all cases, however, the additional 
different names have been reserved and arranged as synonyms. 
CLASSIFICATION MATERIAL 
In this study seven hundred and thirty-one specimens, very many of 
them alike in name, have been classified. By far the largest number of 
these specimens, or so-called varieties, were brought together in 1909 at 
the Nebraska Agricultural Experiment Station, by Professor E. G. Mont- 
gomery and M. S. Jussell, who began their classification and laid the 
foundation for the present work. In making the collection, seeds were 
obtained of all varieties grown by forty experiment stations and of those 
sold by fifty-three seed houses. The original collection included all varie- 
ties then grown or offered for sale in the United States. In 1912 a dupli- 
cate collection was sent by the Nebraska station to the Office of Cereal 
Investigations, United States Department of Agriculture, and in that 
year the varieties were grown on the government experimental fields at 
Arlington, Virginia, and also at the Iowa Agricultural Experiment Station, 
at Ames, Iowa. In the following year, 1913, a duplicate collection was 
sent by the Office of Cereal Investigations to the Department of Plant 
Breeding at Cornell University. The varieties were grown in the plant- 
breeding field during the summer of 1913, at which time they were trans- 
