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not been reported in the United States nor is it found in Canada as far as 

 the experience of the writer goes. Some regard this rust as also a biologic 

 form of Puccinia rubigo-vera. 



The Leaf Rust of Rye (Puccinia rubigo-vera secalis: Puccinia dis- 

 persa). This species closely resembles the leaf rust of wheat in appearance, 

 but is a biologic form as it will not attack other grains. It was found 

 rather common on rye in the uredinal stage, but the teleutosporic stage 

 was rarely collected. In Europe the aecidial stage is in Anchiisa officinalis 

 and Lycopsis asvensis. It may be that the European and American forms 

 are similar though that has not yet been proved. 



Leaf Rust of Oats {Puccinia Lolii: Puccinia coronata). This is a two 

 host rust with the aecidial stage in Buckthorn species (Rhamnus). The 

 uredospores and teleutospores are produced abundantly in the leaves of 

 oats. The teleutospore masses do not break through the epidermis as 

 in the stem rust of grains. ■ The teleutospores can be easily recognised 

 under the microscope as they are provided with projections at the apex, 

 hence the rust is sometimes called the crown rust of oats. 



Both stages of this rust are rather common in late sown oats in the 

 College farm, but the early oats were not attacked. The aecidial stage 

 in the barberry is usually present in the Buckthorn shrubs on the College 

 campus. 



The Leaf Rust of Barley (Puccinia rubigo-vera simplex: Puccinia 

 simplex). This rust occurs on barley in the United States, but there 

 has been no report of it in Canada as far as the writer is aware. 

 Probably it occurs, however, and has been overlooked. It is much 

 like the leaf rust of wheat, but the teleutospores are frequently one celled 

 and infection experiments have shown it to be biologically distinct. The 

 aecidial stage is not known. 



Corn Rust (Puccinia sorghi: Puccinia maydis). This rust is more 

 or less common on the leaves of corn but seems to do little damage. The 

 aecidial stage has been known to be on Oxalis. 



Some wheats are more resistant to the attack of rust than others. 

 Some investigators considered that this resistance was due to morpho- 

 logical characters such as thick cuticle, large amount of silica, or small 

 stomata. This view has not been confirmed, in fact there is little doubt 

 that resistance is independent of any discernible characters in that they 

 are of minor importance. Favourable cultural conditions do not lessen 

 rust. In fact, the more vigorous the host, the more severe is likely to be 

 the rust attack. So close is the relation between host and parasite, a 



