14 ^f- Ä-ai H* 0; W « W % 



VIII. Comparative Inoculation Experiments with Varieties 

 or Strains of Common Flax. 



i) J^Literials. In tlicse e.\'[)criinents, the urcdos[)ores on "Pernau", one of 

 the varieties of flax cotnmonl)- cultivated in Hokkaido, were used only as ino- 

 c: dating materials. They were obtained from the Kitami Branch Station of 

 the Hokkaido Agricultiu-al Experiment Station at Nokkeushi in Province Kitami, 

 on August 24, 1924. 



2) f 'arieties or strains of flax which were used in inocidation experiments. 

 The varieties or strains of flax tested were obtained from the following sources: — 



United States Deiiartment of Agriculture 24 varieties or strains. 



Department of Agriculture for Irelanc! 8 „ 



Hokkaido Agricultural Experiment Station 17 ,, 



The Teikoku Seima Kaisha 36 



College farm, Hokkaido Imperial l'ni\'ersity 4 ,, 



The list included duplicates of manj' of the varieties or strains. Plants 

 bearing the same name from tlifferent sources were generally very similar in 

 morphological characters, but there were some cases which differed somewhat 

 from one another. 



3) Sign of susccptidilitr in the experiments. The degree of the severity 

 of the rust was measured on a scale of o tt> 4, in which o denotes immune, 

 and 4 completely susceptible. 



Experiment I. 



The method used was to make a spore suspension of the uredospores and 

 sjiraj- them on the host in the green-house by means of an atomizer. The pots 

 were then covered with bell jars and placed where the temperature ranged be- 

 tween 14^ and 25 ^C. The bell jars were removed after 4S hours. The results 

 are shown in the follow incf table : — 



