Clxxxii PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



uredospores of P. glumarum make their appearance very early 

 in the life of the plant ; in early winter it may be found, but 

 especially in spring. The quantity of these uredospores is very 

 great, and the rustiness of the plants very striking ; but, strange 

 to say, our wheat-growers do not look upon it with much dis- 

 favour at this season, for it is often said to do more good than 

 harm by checking the too luxuriant growth of the plant. But 

 we may be sure that whatever good it may effect in this direction 

 is more than counterbalanced by the injury it does the grain 

 itself later on in the year. The uredo is very conspicuous, 

 because, although the spore beds are very minute, yet they are 

 crowded in great numbers upon long discoloured stripes on the 

 leaves. The spores themselves are yellow and round. 



" The popular name suggested is that of ' Yellow Rust,' and 

 it is a very expressive one. Puccinia dispersa, on the other 

 hand, as its name implies, has its uredospore beds scattered 

 over the surface of the leaves. The spore beds are larger and 

 brown, or yellowish brown in colour. Seen side by side when 

 fresh these two species can be instantly recognised by the naked 

 eye. Professor Eriksson has been kind enough to send me 

 specimens of both species, and during the past autumn I have 

 given some little attention to the matter. Doubtless P. dispersa 

 has hitherto been regarded by us in its uredo stage as P. graminis, 

 while its teleutospores have been confused with those of P. 

 glumarum. Nor is this last mistake surprising, for between 

 the teleutospores of P. glumarum and those of P. dispersa very 

 little morphological difference exists. They are alike in form, 

 in colour, in size, and in the fact that they both germinate in 

 autumn. P. dispersa, however, occurs more frequently scattered 

 on the leaves, while P. glumarum is in lines upon the sheaths. 

 Unfortunately, however, P. dispersa also sometimes occurs on 

 the sheaths, but its spore beds are larger. My attempts this year 

 to get the teleutospores of both species to germinate have been 

 unsuccessful, nor have I been more fortunate in getting P. dispersa 

 to produce its recidiospores on Anchusa vulgaris, although small 

 bundles of affected wheat leaves have been for the past two 

 months placed in contact with young plants of Anchusa grow- 

 ing in the open air. In Sweden P. glumarum appears to be 

 generally the more frequent, but Professor Eriksson tells me 

 that this year P. dispersa is more abundant than he has ever 



