
SEPT. 1899] . ORIGIN OF AUSTRALIAN 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,’ 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® goes so far as to ascribe the “aggressive power” of the 
Scandinavian flora to the fact of that flora having been differentiated 
in the most extensive land-area of the globe, where competition has 
been most severe and long-continued. 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 * has no doubt about this Scandinavian predominance, though 
he is neutral as regards Mr. Darwin’s explanation of it; and Professor 
Tate, who has recorded his recent experiences in Central Australia in 
an ingenious and suggestive 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,” 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 versd. 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,’ how tropical species could have survived, though, as the 
? “Flora of Tasmania,” Introd. Essay, p. ciii. 2 Loe. cit. 
* “Origin of Species,” ed. vi. p. 340. ea lsland i inte; op: ol. 
> “* 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. Soe. xxii. p. 259. 
