

ON A MICROSCOPIC FUNGUS PARASITIC UPON THE 



CUCURBITACE^E. 



By E. Haviland, F.L.S. 



Side by side with the disease which has been so destructive to 

 the maize crops during the past three months, there has existed 

 another disease, affecting, in an almost equally destructive manner, 

 the Cucuibitaceie ; rock and water melons, and pumpkins alike 

 being destroyed in large quantities by its ravages. Singularly, 

 both diseases have traversed the same tract of country, from the 

 near neighbourhood of Sydney northwards to the Tweed River, 

 and westward, so far as I can learn, about forty miles from 

 the coast. 



The practice, so common amongst Australian farmers, of 

 planting pumpkins between the rows of maize ; and the fact 

 that both these and the maize have been attacked at the same 

 time and in the same place, have given rise to the idea that the 

 two diseases are identical. As a matter of fact, however, they are 

 very different ; the destruction of the maize being caused by the 

 micro-fungus Ustilago Candollei, one of the class Coriiomycetes ; 

 while that attacking the Cucurbitacese, is Oidium monilioides of 

 the Hyphomycetes. Although, however, the causes are different, 

 the results are similar ; the destruction of the plant in both cases. 



This fungus, Oidium monilioides, is supposed to be identical 

 with that known as Erysiphe grammis ; and the genus Oidium is 

 now, by most mycologists amalgamated with Erysiphe. They 

 differ in some respects, but the one (Oidium) is considered to be 

 but a younger state of the other. The genus Erysiphe has no 

 less than five different forms of fruit, the multiform threads 

 bearing conidia, asci contained in sporangia, the larger stylospores 

 produced in other sporangia, the smaller stylospores generated in 





