12 McAlpine, Smuts of Australia. [^'"^Ma^'^'" 



tribution in Victoria. There is also a species found on various 

 eucalypts in the Botanic Gardens, Amsterdam, forming a woody 

 tumour at the collar, and this, too, has never been recorded for 

 Australia, the home of the eucalypt. 



DISTRIBUTION OF THE SMUTS. 



This is a branch of the subject in which field naturalists can 

 lend their assistance by forwarding specimens whenever and 

 wherever they come across them. The record is still too imper- 

 fect to allow of the smuts being arranged in their geographical 

 districts, and I have simply contented myself with indicating their 

 distribution in the different States of the Commonwealth. There 

 are 9 genera recorded out of a total of about 19 altogether, and 

 the species are distributed in the different States as follows : — 

 Victoria, 46 ; New South Wales, 23 ; Queensland, 25 ; South 

 Australia, 17 ; Western Australia, 7 ; Tasmania, 19. 



GALL-FORMING SPECIES. 



There are only two gall-forming species known — Melanoj)- 

 sichium mistro-americanum^ on a species of Polygonum from 

 Queensland, and Cintractia crus-galli, occurring on the common 

 Barnyard-grass in New South Wales, and both are adapted for 

 moist situations. 



The former is given in Cooke's " Handbook " as Ustilago 

 emodeiisis, but an exaniinalion of the original type in Kew 

 Herbarium showed it to be quite distinct from the Queensland 

 specimen. Dr. Treub kindly sent me specimens from Java on 

 Volycjonuiii chinense, and they show the clustered outgrowths up 

 to one inch long, forming a swollen head like a Cantharellus. 

 The gall-forming species are also interesting on account of their 

 distribution. The Queensland species was first recorded from 

 South America, as the specific name denotes, then it was found in 

 the United States, and now it has been met with near Brisbane. 



The smut on the Barnyard-grass is widely distributed in the 

 United States, but has only been found elsewhere near Sydney. 



MODES OF INFECTION. 



Any paper dealing with the smuts would be incomplete without 

 a reference to the successful measures that have been devised for 

 preventing many of the smuls in our cereal crops, based upon our 

 knowledge of the modes of infection. 



It is most important to know how infection occurs in order to 

 prevent it, and this is mainly determined by experiments in the 

 field. If the spores, for instance, are on the grain, and they 

 germinate with it, so that the germ-tube can penetrate the tender 

 seedling, then the evident course is to prevent the germination of 

 the spores by some " steep," such as bluestone. There are at 

 least four principal modes of infection known at the present 

 time — 



