494 ISLAND LIFE 



Joseph Hooker remarks : — " What differences there are 

 in jconditions woukl, judging from analogy with other 

 countries, favour the idea that South-eastern Australia, 

 from its far greater area, many large rivers, extensive 

 tracts of mountainous country and humid forests, would 

 present much the most extensive flora, of which only the 

 drier types could extend into South-western Australia. 

 But such is not the case ; for though the far greater area is 

 niTich the best explored, presents more varied conditions, 

 and is tenanted by a larger number of Natural Orders and 

 genera, these contain fewer species by several hundreds."^ 



The fewer genera of South-western Australia are due 

 almost wholly to the absence of the numerous European, 

 Antarctic, and South-American types found in the south- 

 eastern region, while in purely Australian types 

 it is far the richer, for while it contains most of those 

 found in the east it has a large number altogether 

 peculiar to it ; and Sir Joseph Hooker states that 

 ''there are about ISO genera, out of 600 in South- 

 western Australia, that are either not found at all in 

 South-eastern, or that are represented there by a very few 

 species only, and these 180 genera include nearly 1,100 

 species." 



Geological Explanation of tlw Differences of these Ttvo 

 Floras. — These facts again clearly point to the conclusion 

 that South-western Australia is the remnaot of the more 

 extensive and more isolated portion of the continent in 

 which the peculiar Australian flora was principally 

 developed. The existence there of a very large area of 

 granite — 800 miles in length by nearly 500 in maximum 

 width with detached masses 200 miles to the north and 

 500 miles to the east — indicates such an extension ; for these 



^ Sir Josepli Hooker thinks that later discoveries in the Australian Alps 

 and other parts of East and South Australia may have greatly nioditied or 

 perhaps reversed the above estimate, and the fic^ures f,dven in the preced- 

 ing note indicate that this is so. But still, the small area of South-west 

 Australia will l)c, proitortionally, far the richer of the two. It is much to 

 Ije desired that the enormous mass of facts contained in Mr. Bentham's 

 Flora Australicnsis and Baron von Miieller's Coisus should be tabulated 

 and comi)ared by some competent botanist, so as to exhibit the various 

 relations of its wonderful vegetation in the same manner as was done by 

 Sir Joseph Hooker with the materials available twenty-one years ago. 



