BLACK STEM KU8T OF AGROPYRON AND ELYMUS. 



15 



Black Stem Rust of Ac.kopyuon and Elymus. 



At least three and piobal)ly four ditterent rusts occur on the species 

 of these two grass genera, and are often so closely associated that 

 their accurate identitication is extremely difficult. Of the herbarium 

 specimens of these rusts throughout the country, probabl}' not one in 

 fifty is identified with any certainty. The writer's experiments with 

 these forms are still incomplete, but a few things at least haYC been 

 established. When these grasses are brought under cultivation the 

 changed conditions and proximity to other grasses and grains cause 

 them to become much more rusted than is ordinarily the case. In 

 the cultivated grass plats at the experiment stations in Oklahoma, 

 Kansas, and Nebraska the rusts were found in great abundance. It 

 was therefore eas}^ to carrj' on many culture experiments. These 

 experiments with the uredospores of black stem rust were sufficientl}'^ 

 numerous to make it desirable to arrange them in the following table: 



Tahle I. — Culture experiments ivith black stem rust of Agrojryron and Elymus. 



Datf. 



Jan. 9, 1897.. 



Do 



Jan. 22, 1897 . 



Do 



Do 



Do 



Sept. 13, 1897 . . 



Do 



Oct. 5, 1897 . . . . 



Do 



Locality. 



Origin of inoculating 

 material. 



Washington, D. C. . 



do 



do 



do 



do 



do... 



Stillwater, Okla .. 

 do 



Manhattan, Kans 

 do 



Do do 



Do do 



Oct. 21, 1897....' do 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Nov. 24, 1897 

 Jan. 5, 1898.. 



Do 



Jan. 21, 1898. 



do , 



do 



do , 



do 



do 



....do 



....do 



Lincoln, Nebr 



....do 



.do. 



-do. 



Do 



Feb. 11, 1898. 



Do. 

 Do. 

 Do. 



Do. 



Do. 

 Do. 



Do. 

 Do. 

 Do. 



.do. 

 -do. 



.do. 

 .do. 

 .do. 

 .do. 



.do. 

 .do. 



.do. 

 .do. 

 .do. 



Wheat. 

 ....do. 

 ....do. 

 ....do. 



do 



do 



Agropyron tcneriim — 



Afiropyron oecidentale 

 Wheat (originally 

 Agropiirrm trncrum). 

 do 



.do. 

 .do , 

 .do. 

 -do. 

 .do. 



Agropyron oecidentale 



do 



do 



do 



do 



Elynms canadensis 



f/laucifolius. 



do 



Wheat (originally 



Elymus canadensis 



glducifolius). 



do 



Elymus canadensis 



glaucifolius. 



do 



do 



do 



do 



.do. 

 .do. 



.do. 

 .do. 

 .do. 



Plant inoculated. 



Elymus virginicus 



Wheat 



Elymus virginicus 



Agropyron richard- 

 snni. 



Wheat 



Agropi/ron oecidentale 



Wheat 



Af/ropi/ron tenerum .. 



Wheat 



do 



Barley 



Aqropiiron tenerum . . 



Wheat 



Barlev 



Oats .". 



Rve 



Wheat 



Rye 



Barley 



Agropyron tenerum .. 

 Agrop >/ronocc id en tale 

 Wheat 



Barley. 

 Wheat. 



Barlev. 

 Wheat. 



Barley 



Rye 



Oats 



Elymus canadensis 

 glaucifolius. 



Elymus virginicus 



Elymus virgin i cus 

 muticus. 



Elymus inlermedius. . 



Agropyron tenerum . . 



Agropyron oeciden- 

 tale. 



Period 

 of incu- 

 bation 

 in days. 



10 

 10 

 11 

 11 



U 



11 



6 



6 



12 



8 

 8 

 16 

 16 

 16 

 16 

 18 

 18 

 18 

 18 

 15 

 21 



21 

 10 



10 

 14 



14 

 14 

 14 

 14 



14 

 14 

 14 



Result. 



Success. 

 Do. 

 Do. 

 Do. 



Do. 

 Failure. 

 Success, a 



Do. 

 Failure. 

 Success. 



(ft) 



Failure, c 

 Success. 



Do. 

 (d) 

 Failure. 



Do. 



Do. 



Do. 



Do. 

 Success. 



Do. c 



Do. 

 Do. 



Do. 



Do./ 



Do. 

 Failure. 



Do. 

 Success. 



14 [ Failure. 

 14 I Do. 



Do. 

 Do. 

 Do. 



aPustules differ in color from the original. 



bl pustule only. 



"Conditions very unfavorable, however. 



rt Apparently 1 pustule formed. 



e Rust changes color and form of pustule. 



/ Rust changes color, 



