CLASSIFICATION" OF AMERICAN" WHEAT VARIETIES. 13 



emergence, heading, ripening, and height of the many varieties. 

 During the summer the writers visited the various points and took 

 detailed notes on the characters of the varieties. It was here, in the 

 field, that the descriptions of the varieties were written and the keys 

 designed and perfected to distinguish the different varieties. The 

 descriptions were checked and rechecked at the various points and 

 the different descriptive classes were established on a basis broad 

 enough to include the varieties wherever they were grown. 



NATURE OF THE MATERIAL. 



The early studies showed the necessity of working with pure lines. 

 When bulk seed was used it often consisted of mixed varieties and 

 a wrong description might easily become applied to a variety. For 

 that reason careful notes were made on the material that was sown in 

 each nursery. A typewritten outline was prepared each year which 

 showed the classified arrangement of the varieties based on the re- 

 sults to date and also the row numbers at each station. The same 

 variety often was represented by different lots of seed obtained from 

 different sources. These were distinguished by different C. I. numbers, 

 which are accession numbers of the Office of Cereal Investigations. 

 The varieties, however, have always been distinguished by names 

 rather than by numbers. For this reason Cereal Investigations 

 numbers are not used in this publication. The nursery outlines also 

 contained columns showing the source of the seed sown and the orig- 

 inal source of the variety. In addition, they showed whether the 

 seed sown was bulk grain or a pure line, and if a pure line, whether 

 the same pure line was sown at all stations or whether different pure 

 lines were used. In this way it was easily possible to compare field 

 notes accurately with those of the previous year or to account for 

 differences which existed in the same variety at different stations in 

 the same year. This latter condition often occurred when bulk grain 

 or different pure lines were used. Natural field hybrids thus were 

 easily distinguished from mixtures. 



formerly scientific assistant, in charge of the cereal nursery at the Amarillo Oereal Field 

 station, Amarillo, Tex. ; Mr. A. D. Ellison, formerly scientific assistant, Mr. H. P. Ames, 

 formerly agent, and Mr. J. W. Taylor, scientific assistant, respectively, in charge of the 

 CCteal investigations at tin- Arlington Kxperimental Farm, near Rosslyn, Va. ; Dr. II. II. 

 Love, professor of plant breeding, and Mr. W. T. Craig, agent, Cornell University, 

 Ithaca, N. Y. 



The writers also acknowledge with gratitude the assistance received from the follow- 

 ing officers of the State experiment stations not formally cooperating with the Office of 

 Cereal Investigations: Prof. G. B. Hyalop, professor of farm crops, and Prof. C. C. Ruth, 

 assistant professor <,f farm crops, at the Oregon Agricultural Experiment Station, Cor- 

 vallis, Oreg. ; Prof, K. P. Gaines, assistant professor of farm crops at the Washington 

 Agricultural Experiment Station, Pullman, Wash.; I'rof. P. V. Cardon, agronomist at the 

 Montana Agricultural Experiment Station, I'.ozcnian, Mont.; Mr. I'.rcey.e Jioyack, formerly 

 assistant agronomist at the Colorado Agricultural Experiment Station, Fori. CoIIIiik, 

 Colo.; and Prof. S. C. Salmon, professor of farm crops at the Kansas Agricultural Experi- 

 ment Station, Manhattan, Kans. 



