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THE ROYAL SOCIETY OF CANADA 



occurs early enough in the season to cause material damage. Ob- 

 viously, the group of rust strains just considered should constitute 

 the first point of attack for the plant breeders. The winning of this 

 objective should go a long way towards the solution of the general 

 problem. 



The distribution of the 8 remaining forms is shown in Figs. 2, 

 A and B, A key to the symbols employed is given in the lower 

 right-hand corner. On the whole, these forms were rather widely 

 scattered, although Form IX, which attacks emmer heavily, appar- 

 ently was more prevalent in the eastern half of the wheat area than 



Fig. 2. Localities in which have been collected the forms not included in Fig. 1. 



