sept. 1899] ORIGIN 01 AUSTRAIIAN FLORA 199 



existence. It is proposed now to throw the search-light of analysis 

 upon this theory, with the object of ascertaining whether it rests on a 

 real substantive basis or no. 



The first point to be dealt with is the idea that species belonging 

 to genera predominantly extra-Australian must necessarily have had 

 their origin outside Australia, whither they have migrated, some in- 

 herent superiority possessed by them over forms truly endemic 

 having enabled them to maintain themselves and gain ground in their 

 new home. In this relation the two floras of special concern are the 

 Scandinavian and the Indo-Malayan. " The Scandinavian asserts his 

 privilege of ubiquity," writes Sir Joseph Hooker, 1 and the same botanist 

 tells us he regards " the Indian plants in Australia to be as foreign to 

 it, botanically, as the Scandinavian, and more so than the Antarctic." 

 Mr. Darwin 3 goes so far as to ascribe the " aggressive power " of the 

 Scandinavian flora to the fact of that flora having been differentiated 

 iu the most extensive land-area of the globe, where competition has 

 been most severe and long-contiimed. But the supposed long con- 

 tinuance of this competition traverses well-established geological data, 

 which teach us that the undisputed sway of this flora over Northern 

 Europe and Asia dates only from post-Miocene times ; while as regards 

 the nature of the competition, who can possibly say that European 

 plants have been subjected to greater stress than those of the old and 

 new world tropics, of South Africa, or of Australia itself? Mr. 

 Wallace 4 has no doubt about this Scandinavian predominance, though 

 he is neutral as regards Mr. Darwin's explanation of it ; and Professor 

 Tate, 5 who has recorded his recent experiences in Central Australia in 

 an ingenious and suo-oestive memoir, finds warrant for the belief that an 

 exotic vegetation is there gaining the upper hand over the indigenous 

 flora. In the face of such authority, and more could be cited were 

 it necessary,' 5 it will, I hope, be believed that the attempt here made 

 to maintain a contrary opinion is undertaken in a spirit of diffidence, 

 and without the slightest desire of asserting a rebellious originality. 



It is not to be doubted that during past ages facilities have existed 

 for the transport of northern forms through the tropical highlands into 

 southern countries and vice versa. Whether this migration has been 

 largely favoured by cooling of the tropics during glacial periods, or 

 whether, as is perhaps more plausible, it has been in great part due to 

 transport by ordinary agencies such as the winds, the movements of 

 birds, etc., is not a question we have here to discuss. Under the 

 first supposition it is difficult to understand, as Sir Joseph Hooker has 

 pointed out, 7 how tropical species could have survived, though, as the 



1 "Flora of Tasmania," Introd. Essay, p. ciii. - Loc. cit. 



3 " Origin of Species," ed. vi. p. 340. 4 " Island Life," p. 511. 



5 " Botany of the Horn Expedition," p. 120. 



6 These remarks being of the nature of suggestions merely, I have refrained from 

 quoting bibliography except when that course seemed unavoidable. 



7 Trans. Linn. Soc. xxii. p. 259. 



uj LIBRARY r;] 



