50 



THE RUSTS OF GRAINS IN THE UNITED STATES. 



Dates of collection and germination and summar}^ of results are 

 given in Tables TV and Y. 



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



Minn. 



Date of collection and germination 

 test. 



Species. 



November 20, 1906. 

 December 14, 1906.. 

 December 27, 1906.. 

 January 2.5, 1907.... 

 February 15, 1907.. 



March 16, 1907 



AprU 15,1907 



Noyember 20, 1906. 

 December 14, 1906.. 

 December 27, 1906.. 

 January 25, 1907.... 

 February 15, 1907.. 



March 16, 1907 



April 15, 1907 



November 20, 1906. 

 December 14, 1906. . 

 December 27, 1906.. 



January 25, 1907 



February 15, 1907.. 



March 16, 1907 



April 15, 1907 



November 29, 1906. 

 December 14, 1906. . 

 December 27, 1906.. 



January 25, 1907 



February 15, 1907.. 



March 16, 1907 



November 20, 1906. 

 December 14, 1906.. 

 December 27, 1906.. 



January 25, 1907 



February 15, 1907.. 



AprU 16, 1907 



November 20, 1906. 

 December 14, 1906. . 

 December 27, 1906.. 

 January 25,1907..., 

 February 15, 1907. . 

 March 16, 1907 



Pucctnia graminis. 



do 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



....do 



do 



do 



....do 



do 



Host plant. 



Time of 

 incuba- 

 tion. 



P. graminis 



do 



....do 



P. rublgo-vera . 



do 



do 



do 



do 



P. rubigo-vera. 



do 



do 



do 



P. simplex . 



do 



do 



Hordeum jubalum. 



....do 



....do 



....do 



....do 



....do 



....do 



Agropvron repens. . 



. . . .do". 



....do 



....do 



do 



do 



do 



A. teuerum 



do 



do 



A. tenerum . 



....do 



....do 



A. repens. . . 



do 



do 



do 



do...:.. 



Winter wheat . 



....do 



....do 



....do 



Hours. 

 22 

 40 

 24 

 22 

 24 

 18 

 26 

 22 

 40 

 24 

 22 

 24 

 18 

 26 

 48 

 40 

 24 



24 

 18 

 26 

 22 

 40 

 24 

 22 

 24 



40 

 40 

 24 

 22 



Gennuia- 

 tion. 



Per cent. 

 95 

 26 

 50 

 30 

 75 

 50 

 35 

 50 



3 

 G2 



5 

 25 

 50 



5 



5 

 25 

 95 



10 

 25 

 40 

 50 

 10 

 50 

 50 

 



Barley . 

 ....do. 

 ....do. 



40 

 24 



15 

 20 

 12 

 25 



30 

 40 



Table Y. — Summary of germination results from uredo material kept buried in snoiv 



until germination tests u^ere made. 



Date of germination test. 



December 10, 1906. 

 Januarys, 1907.... 

 Fel)ruary 9, 1907 .. 



March 20, 1907 



December 10, 1906. 



January 8, 1907 



February 9, 1907.. 



March 20, 1907 



December 10, 1900. 

 December 10, 1906. 

 January 8, 1907.... 

 February 9, 1907.. 



March 20, 1907 



December 10, 1906. 

 Januarys, HK)7.... 

 February 9, 1907.. 



March 20, 1907 



December 10, 1906. 

 Januarys, 1907.... 

 Fehniaryg, 1907. . 

 March 20, HK)7 



Species. 



I'uccinia graminis. 



....do 



do: 



do 



do 



do 



do 



do 



do 



P. rubigo-vera 



do 



do 



do 



do 



do 



do 



do 



P. simplex 



do 



do 



do 



Host plant. 



Hordeimi jubatum. 



....do.. 



....do 



do 



.\gropyron repens.. 



do". 



....do 



do 



A. teneru7ii 



A. rejjens 



do 



do 



do 



Winter wheat 



do 



do 



do 



Barley 



do 



do 



do 



Tune of 

 incuba- 

 tion. 



Germtna- 

 tioi). 



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 

 5 

 5 

 15 

 25 

 90 

 25 

 75 

 40 

 CO 

 30 

 10 

 50 

 25 

 3 

 5 

 10 

 15 

 10 

 50 

 10 



1216 



