lo McAlpine, Smuts of Australia. [^"^May^'' 



responsible every year for a considerable reduction in the yield of 

 our cereal crops, which, however, can be largely prevented by 

 methods of treatment based upon a knowledge of their life- 

 histories. There is a deal of ungarnered grain owing to their 

 ravages, for the diseases caused by smuts are among the most 

 destructive, since they often destroy the grain itself, which is the 

 chief object of cultivation. 



It is difficult to form a reliable estimate of the losses caused by 

 the smuts, but in one year 1 reckoned that the stinking smut of 

 wheat alone cost Victoria ^f 50,000, and Swingle has estimated 

 the annual loss by oat smut to the United States at ^3,384,521. 



DIFFERENCES BETWEEN SMUTS AND RUSTS. 



There is so much in common between the smuts and the rusts 

 that they are often confounded. They are both parasitic fungi, 

 both produce clusters of spores, which are often black or dark 

 coloured, and the spores of both germinate in a somewhat similar 

 fashion. It is not to be wondered at, then, that the ordinary 

 observer does not distinguish the difference, and while it is neces- 

 sary to make a final appeal to the microscope to settle the 

 difference, I consider that, for all practical purposes, smuts may 

 be generally recognized by the black masses of spores, all of one 

 kind, and not a variety of forms, as happens in many of the rusts, 

 especially if one has familiarized himself with the naked-eye 

 appearances in a good herbarium. Smut is readily recognized in 

 the inflorescence of grasses, for instance, which is often converted 

 into a sooty, powdery mass, from the development of the spores in 

 that particular region. 



It may be some consolation to the novice to know that even 

 experts may be misled by the resemblance, and have mistaken 

 smuts for rusts, and vice versd. Thus, there is the well-known 

 fiag smut, which occurs on the wheat, and it is quite commonly 

 called " black rust" by farmers and others, but the character of 

 the spores, seen under the microscope or in a good photograph, 

 surrounded by its bladder-like cells, would exclude it from the 

 rusts at once. Then the not uncommon maize rust has been 

 mistaken for a smut by such eminent investigators as Berkeley 

 and Broome and Massee. Mr. Bailey, of Queensland, sent a 

 specimen to Britain for determination, and he wrote me concern- 

 ing it as follows : — " In the year 1878 the maize about Brisbane 

 was infested with a Uredo, which Messrs. Berkeley and Broome 

 determined to be Uredo mcif/dis, D.C. After this these two 

 specialists found the maize fungus to be a new Tilletia, and 

 described it as Tilletia epiphylla, B. and Br." Then Massee, of 

 Kew, afterwards supported this determination, noting that the 

 pustules resembled a rust superficially. If he had only observed 

 the germ-pores of the spore, as shown in the photograph obtained 

 from a type specimen, he woukl have seen that there was more 



