CLASSIFICATION OF AMERICAN WHEAT VARIETIES. 9 



and stated whether they were bearded or smooth, and also the color 

 of the grain and chaff, the height of the plant, and the weight of the 

 kernels. 



Clark, Stephens, and Florell, in 1920 (67), gave a tabular descrip- 

 tion of over 150 samples of Australian wheat varieties grown in ex- 

 periments in the Pacific coast area of the United States. 



Clark, Martin, and Smith, in 1920 (66), keyed the groups of com- 

 mon spring and durum wheat grown in experiments in the northern 

 Great Plains area of the United States, and gave the histories of the 

 principal varieties. 



Stewart, in 1920 (187), presented keys and brief descriptions of 

 the commercial wheat varieties grown in Utah. 



SUMMARY OF PREVIOUS CLASSIFICATIONS. 



From the beginning of botanical classification there was a tendency 

 to regard the different forms of Avheat as distinct species. Toward 

 the end of the eighteenth century there became evident a tendency 

 toward the more reasonable view that comparatively few species were 

 involved and that the evident major groups were mostly to be re- 

 garded as subdivisions of the species sativum of Lamarck or vulgare 

 of Villars. 



The making of botanic species of wheat was carried to great lengths 

 by the botanists of 100 to 200 years ago, who did not recognize that 

 the characters sufficient to separate species of wild plants were suffi- 

 cient to separate only agronomic and horticultural varieties of domes- 

 ticated plants. Before this fact was recognized and botanists very 

 largely had ceased to deal with the forms of cultivated plants, some 

 50 or 60 supposed species of wheat had been described. 



In the works of most of the botanists there was little effort to study 

 and describe the farm varieties of wheat. However, Heuze, Koer- 

 nicke and Werner, Eriksson, Richardson, and others described many 

 varieties, and some of their descriptions were fairly complete. No 

 attempt has been made, however, previous to the present work, to 

 show by detailed keys and by uniform descriptions the minor differ- 

 ences which separate closely related varieties. 



There has been wide diversity among botanists in the taxonomic 

 use of the various morphological characters of the wheat plant and 

 seed. Only a few authors have given attention to the winter or 

 spring habit of growth in wheat varieties. Some, as Eriksson, have 

 placed undue importance on differences in spike density. Many 

 writers have made no use of the colors of the seed coat in separating 

 varieties. 



The classification of Koernicke and Werner is the most extensive 

 and the only one which made a definite attempt to describe and 

 classify foreign and domestic farm varieties. While conservative 



