50 



THE BUSTS OF GRAINS IN THE UNITED STATES. 



Dates of collection and germination and summary of results are 

 given in Tables IV and V. 



Table IV. — Summary of experiments on the wintering of the uredospore at St. Paul, 



Minn. 



Date of collection and germination 



test. 



Species. 



Host plant. 



Time of 

 incuba- 

 tion. 



Germina- 

 tion. 



November 20, 1906 



Puccinia graminis 



do 



Hordeum jubatum 



do 



Hours. 

 22 

 40 

 24 

 22 

 24 

 18 

 26 

 22 

 40 

 24 

 22 

 24 

 18 

 26 

 48 

 40 

 24 



Per cent. 

 95 



December 14, 1906 



26 



December 27, 1906 



do 



do 



50 



January 25, 1907 



do 



do 



30 



February 15, 1907 



do 



do 



75 



March 16, 1907... 



do 



do 



50 



April 15, 1907 



do 



do 



35 



November 20, 1906 



do 



Agropyron repens 



do 



50 



December 14, 1906 



do 



3 



December 27, 1906 



do 



do 



32 



January 25, 1907 



do 



do 



5 



February 15, 1907 



.....do 



...do 



25 



March 16, 1907 



do 



do 



50 



April 15, 1907 



do 



do 



5 



November 20, 1906 



do 



...do 





5 



December 14, 1906 



do 



25 



December 27, 1906 



do 



...do 



95 



January 25, 1907 









February 15, 1907... . 







24 

 18 

 26 

 22 

 40 

 24 

 22 

 24 



10 



March 16, 1907 



do 



...do 



25 



April 15, 1907 



:do 



...do 



40 



November 29, 1906 



P. rubigo-vera 



do . 





50 



December 14, 1906 . . 



.do . 



10 



December 27, 1906. . . 



...do... 



...do... 



50 



January 25, 1907 



do 



....do 



50 



February 15, 1907 



do 



do 







March 16, 1907... 









November 20, 1906 



P. rubigo-vera 



do 



..do... 





40 

 40 

 24 

 22 



15 



December 14, 1906 



December 27, 1906 .. 



do 



.do .. 



20 

 12 



January 25, 1907... 



...do... 



...do... 



25 



February 15, 1907 









April 16, 1907 











November 20, 1906. . . 











December 14, 1906. . . 



do 



do 



40 



24 



30 



December 27, 1906 



do 



. do 



40 



January 25, 1907 .. 









February 15, 1907 











March 10, 1907 





















Table V. — Summary of germination results from uredo material kept buried in snow 

 until germination tests were made. 



Date of germination test. 



Species. 



Host plant. 



Time of 

 incuba- 

 tion. 



Germina- 

 tion. 



December 10, 1906 



Puccinia graminis 



do 



Hordeum jubatum 



do 



Hours. 

 20 

 24 

 24 

 20 

 20 

 24 

 24 

 20 

 20 

 20 

 24 

 24 

 20 

 20 

 24 

 24 

 20 

 20 

 20 

 24 

 20 



Per cent. 

 50 



January 8, 1907 



5 



February 9, 1907 



...do .. 



....do 



5 



March 20, 1907 



...do 



.....do 



15 



December 10, 1906 



do 



Agropyron repens 



do 



25 



January 8, 1907. 



...do 



90 



February 9, 1907 



March 20, 1907 



do 



do 



do 



do 



25 

 75 



December 10, 1906 



...do .. 





40 



December 10, 1906 



P. rubigo-vera 





60 



January 8, ^907 



...do 



30 



February 9, 1907 



...do 



do.... 



...do 



10 



March 20, 1907 



do 



50 



December 10, 1906 



.. do .„ 





25 



January 8, 1907 '. 



...do 



do 



3 



February 9, 1907 



do , 



.....do 



do 



5 



March 20, 1907 



do 



10 



December 10, 1906 







15 



Januarv 8, 1907 



do 



do 



10 



February 9, 1907 



do 



...do 



50 



March 20, 1907 



do 



do 



10 











216 



