Section V, 1922 [153] Trans. R.S.C. 



XVII. Studies in Wheat Stem Rust {Puccinia Graminis Tritici) 



By Margaret Newton, M.A. 



Presented by W. P. Thompson, Ph.D., F.R.S.C. 



(Read May Meeting, 1922) 



TABLE OF CONTENTS 



Part I. Biologic Forms of Wheat Stem Rust (Puccinia Graminis 



Tritici) in Western Canada 



page 



Introduction 154 



Historical Summary 155 



Importance of the Present Investigation 157 



Experimental Materials and Methods 158 



Differential Hosts 158 



Table I. List of Differential Hosts 158 



Table II. Explanation of Symbols Used to Indicate 



Types and Degrees of Infection 159 



Analytical Key to Biologic Forms 160 



Results 161 



Table HI. Distribution and Infection Capabilities of 



the Biologic Forms 162 



Identity and Nature of the Forms Isolated 166 



Diagrams of Inoculation Series 168 



Importance of Forms Isolated 183 



Varietal Range and Virulence • • 183 



Distribution and Frequency 184 



Figure I. Distribution Maps 185 



Figure II. Distribution Maps 186 



Figure III. Graphic Representation of Virulence and 



Frequency of Forms 187 



Infection on Grasses 188 



Summary of Points of Special Economic Importance (Table IV). 189 



Discussion of the Principal Issues 191 



Table V. Results of Inoculations on Grasses 192 



Summary of Part I 196 



