By J. ARTHUR HARRIS, headj Department of Botany, University of Minnesota, and collaborator, Bureau of Plant Industry, U. S. Department of Agriculture; CLARA T. HOFFMAN, field assistant, Office of Alkali and Drought-Resistant Plant InvestigationSy Bureau of Plant Industry, U. S. Department of Agriculture (1923-24); and WALTER F. HOFFMAN", assistant agricultural biochemist, Division of Agricultur...