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The rusts have become adapted to certain grains, and will not grow readily 

 on other grains or grasses, so that the stem fusts of cereals consists of a 

 number of biologic forms as they are called. 



According to experiments carried on by the United States Depart- 

 ment of Agriculture there are the following biologic forms of the stem 

 rust of grains in the United States: — 



The Stem Rust of Wheat (Puccinia graminis fritici) on wheat, 

 also attacks barley and rye sparingly. 



The Stem Rust of Oats (Puccinia graminis avenae) on oats and 

 some grasses. 



The Stem Rust of Barley {Puccinia graminis hordei) on barley, 

 also attacks wheat and rye readily. 



The Stem Rust of Rye {Puccinia graminis secalis) on rye, also barley. 



No extensive experiments have been carried out in Canada as far 

 as the writer is aware, to determine the forms of stem rust occurring here, 

 but is it probable that they do not differ much from those in the United 

 States. 



All of these biologic forms will pass to the barberry, but it has been 

 found by most investigators that they behave in exactly the same manner 

 after being transferred through the barberry as they do in the uredinial 

 stage. With material obtained from oats growing at Ste. Annes, the 

 writer infected barberry and trials with the uredospores thus obtained 

 failed to infect wheat, barley and several grasses though infection was 

 obtained readily in oats. 



The stem rust is usually common on the oats and barley grown in 

 the College farm. It is not nearly so common on wheat and rye. 



The Leaf Rust of Wheat {Puccinia rubigo-vera tritici; Puccinia 

 triticina) On wheat but will attack barley and rye. 



The leaf rust of wheat is especially common on wheat in Eastern 

 Canada, much more common in the writer's experience than the stem 

 rust. The uredospore stage is more common and conspicuous than the 

 teleutospore stage. The later stage is found in the leaves and sheath 

 about the time the wheat is r pe, but the masses of teleutospores do not 

 rupture the epidermis and being thus inconspicuous are. often overlooked. 

 The uredospores also occur on the leaves. There is supposed to be an 

 aecidial stage corresponding to the stage of the stem rust in the barberry, 

 but nothing is known of it. The Yellow Rust of Wheat {Puccinia glu- 

 marum) which is common and destructive in Europe and India but has 



