ORANGE LEAF RUST OF AGROPYRON AND ELYMUS. 



17 



Orange Leaf Rust of Agropyron and Elymus. 



In the following table are summarized the results of inoculations 

 with the uredoform of this rust. They were carried on simultaneously 

 with those of the black stem rust, and the material was taken chiefly 

 from the same individual host plants. 



Table II. — Culture experiments with orange leaf rust of Agropyron and Elymus. 



Date. 



Locality. 



Origin of inoculating 

 material. 



Plant inoculated. 



Period 

 of incu- 

 bation 

 in days. 



Result. 



Dec 21 1896 



Washington, D.C 

 ...do 



Rye 



Elymus americanus . . 



Rye 



Elymus virginicus 



Rye 



Elym us virginicus 



Rye 



. 16 

 16 

 12 

 12 

 13 

 13 

 18 



18 

 18 

 12 

 12 



12 

 12 

 26 

 26 



9 

 9 

 9 



21 

 21 

 18 

 18 



14 

 14 

 14 



14 



Failure. 



Do 



do 



Success. 



Jan 7 1897 



do 



...do 





Do 



..do . 



...do 



Success. 



Feb. 1,1897... 



...do 



do 



Failure. 



Do 



do 



do 





Feb. 13, 1897.... 

 Do 



do 



Wheat . . . 



Agropyron richard- 

 soni. 



Wheat 



Rye 



Agropyron tenerum. . . 



Triticum villosum 



Elymus canadensis . . . 

 Rye 





do 



do 





Do 



...do. . 



do 





Feb. 20, 1897.... 

 Do 



do 



Rye 



Do. 



...do 



do 



Do. 



Do... 



.....do 



do 



Do. 



Do 



. .do ... 



do 





Mar. 30, 1897 . . . 

 Do 



.do 



do 



Agropyron caninum.. 

 Rye... 



Failure. 



do 



...do 





Nov. 3, 1897 .... 

 Do 



Manhattan, Kans.. 

 do 



do 



Wheat 





do 





Do. 



Do 



do . 



. .do... 



Agropyron tenerum. . . 

 Rye 



Do. 



Do 



...do ... 



....do 





Jan 5, 1898 



Lincoln, Nebr 



...do ... 



do . 



do ... 



Do. 



Do.. 



...do ... 



Elymus virginicus 



Wheat 





Mar 4 189X 



do 



Elymus virginicus 



Elymus canadensis 



glaucifoiius. 

 Wheat 



Do. 



Do. 



.do 



do 



Do. 



Mar. 12, 1898... 



...do . 



do 





Do 



...do ... 



do 



Elymus canadensis . . . 

 Elymus canadensis 



glaucifoiius. 

 Agropyron tenerum . . 





Do 



do 



do 



Do. 



Do.. 



do ... 



do 



Do. 











The chief conclusion to be derived from the results of these cultures 

 is that the orange leaf rust is very sharply limited in its host adap- 

 tation and differs widely in this respect from the black stem rust. 

 Similar results are given in Bulletin No. 16 of the Division of Vege- 

 table Physiology and Pathology, U. S. Department of Agriculture, 

 for cultures of the forms on wheat and rye. In fact, it is quite proba- 

 ble that almost every distinct host species bears a distinct form of the 

 rust. One of these forms on Elymus virginicus L. has recently been 

 found by Doctor Arthur to be connected with the iEcidiutn on Imjxi- 

 tiens aurea Muhl. and is now to be known as Puccinia impatientis 

 (Schw.) Arth. * 



Black Stem Rust of Agrostis alba vulgaris. 



Culture experiments with the uredoform of this rust and observa- 

 tions in the field indicate that it is distinct and does not occur on other 



a Botanical Gazette, vol. 35, pp. 18-19, January, 1903. 

 27787— No. 63—04 2 



