648 ON THE MYRTACE/E OF AUSTRALIA. 



thoroughly examined and described, for, in the opinion of Baron 

 Mueller, there are probably some thirty species yet to be added to 

 the genus, though many of them are only small trees or shrubs. 

 How many of these may be endemic has to be determined, but it 

 seems tolerably certain, that in Eucalyptus, as well as in the 

 Myrtacere generally W. Australia will predominate over the other 

 colonies in the number and peculiarity of the species. Other 

 orders of plants / common to W, Australia and South Africa, led 

 Sir Joseph Hooker to offer a speculative theory as to the probability 

 " that the peculiar Australian Flora may have inhabited an area 

 to the westward of the present Australian Continent." Since the 

 publication of Hooker's Essay in 1859, the Flora of Australia has 

 been zealously elucidated by the labours of Mr. Bentham and 

 Baron Mueller, and the former, in the concluding preface to the 

 last volume of the Flora Australiensis, gives it as his opinion 

 " that the predominant portion appears to be strictly indigenous. 

 Notwithstanding an evident though very remote ordinal tribual or 

 generic connection with Africa, the great mass of purely Australian 

 species and endemic genera, must have originated or been differen- 

 tiated in Australia, and never have spread far out of it." 

 Eucalyptus, indeed, as already remarked is somewhat exceptional 

 as regards Timor and New Guinea, but so far as the Myrtacese are 

 considered generally, the capsular genera, comprehending the vast 

 majority of species in all parts of the continent are almost 

 exclusively Australian. How far the labours of geology may assist 

 in determining the comparative age of our Flora, its connection 

 with forms of vegetation long past, and its distribution in different 

 regions, remains yet to be seen. 



