Aug. 2 7, 191 7 Puccinia graminis on Cereals and Grasses 



459 



Table XXV. — Results of inoculations with urediniospores from Secale cereale L. 



a Minute uredinia. 

 Diagram ii. — Results of inoculations with rust developed in No. 6, Table XXV. 



Rye - 



'4 



Puccinia graminis from Secale ccreah' 



Barley j^ 



Wheat — 



I 6 



I Wheat — 



Wheat tA I 



^^Rye — . 



Rye is usually affected with P. graminis secalis in the field. It will be 

 noticed that the rust infects barley very readily and can infect oats only 

 occasionally and with difficulty. The uredinia on oats were all very 

 small. P. graminis iritici may also occur rarely on rye. The fact that 

 the wheat stemrust and not the rye stemrust infected wheat in No. 6 in 

 Table XXV is shown in diagram ii. The rust on barley was all the rye 

 form, since it could not infect wheat. The rust on the wheat, however, 

 was clearly P. graminis iritici, since it infected wheat but produced only 

 two flecks on rye. The very limited infection of rye by wheat stemrust 

 in the field is probably of little practical consequence. 



The inoculations reported in diagram 12 were made with aeciospores 

 developed on Berberis vulgaris as a result of inoculations with teliospore 

 material which was sent by Dr. J. C. Arthur, of Purdue University. It 

 could be seen that the rust was unquestionably P. graminis secalis. The 

 reason for the failure on the one rye leaf inoculated directly with aecio- 

 spores was that this leaf died early, thus making the trial inconclusive. 

 However, the subsequent infection on rye as a result of inoculations 



