BIOLOGIC FORMS 19 



soil seems to indicate that here, as well as in the case of rye, inoculated 

 with oat rust, the mycelium is enabled to develop more extensively 

 and possibly produce more spores than when ordinary soil is used. 



INOCULATIONS ON BARLEY 



The results of this series of inoculations were very similiar to 

 those obtained by other investigators. The behavior of the rust was 

 typical of its usual behavior on an uncongenial host plant. The flecks 

 were small in nearly all cases and were especially sharp when plants 

 had been exposed to anesthetics. 



Inoculations made under ordinary conditions 



These were not especially successful. No pustules were developed 

 on 50 inoculated leaves but 10 of the leaves became flecked. 



Inoculations after exposure to anesthetics 



Ether and chloroform were used. The period of exposure varied 

 at different times from 5 to 15 minutes. Plants exposed only 5 minutes 

 did not appear different from the check plants. After exposure for 

 15 minutes the flecking was more distinct than on the check plants. 

 Only one pustule developed in the entire number of trials, this being 

 after exposure to ether. There were 47 leaves inoculated after expo- 

 sure to ether, and of these one developed a pustule and 15 were fleck- 

 ed. The flecks in this case had every appearance of unruptured pus- 

 tules. No pustules were developed after exposure to chloroform, 

 but 7 leaves out of 50 became flecked. Of 147 leaves inoculated 32 

 were flecked, but only one showed a pustule. 



SUMMARY OF INOCULATIONS MADE WITH PUCCINIA GRAMINIS AVENAE 

 Oat rust to: 



Wheat -j-J-g- ; 5 flecked 



Wheat after exposure to ether -$ ; 56 flecked 



Wheat after exposure to chloroform -^ ; 19 flecked 



Wheat after leaf injury^; 14 flecked 



Wheat plants grown in manured soil -^V ? 



Barley^; 10 flecked 



Barley after exposure to ether -^ ; 15 flecked 



Barley after exposure to chloroform ^^ j 7 flecked 



Rye -j^- 13 flecked 



Rye after exposure to ether -^- f ; 26 flecked 



Rye after exposure to chloroform ^; 13 flecked 



Rye after exposure to nitrous oxide -f^; 6 flecked 



Rye after leaf injury ^; 14 flecked 



Rye grown in highly fertilized soil - ; 9 flecked 



