chap, xxiii.] ARCTIC PLANTS IN NEW ZEALAND. 
493 
and the lofty equatorial mountains, and mostly at a distant 
period when the conditions for migration were somewhat more 
favourable than they are now. The much greater directness 
of the route from Northern Europe to South Africa than to 
Australia ; and the existence even now of lofty mountains and 
extensive highlands for a large portion of the distance, will 
explain (what Sir Joseph Hooker notes as “a very curious 
fact ”) why South Africa has more very northern European 
genera than Australia, while Australia has more identical 
species and a better representation on the whole of the 
European flora — this being clearly due to the large influx of 
species it has received from the Antarctic Islands, in addition 
to those which have entered it by way of Asia. The greater 
distance of South Africa even now from any of these islands, 
and the much deeper sea to the south of the African continent, 
than in the case of Tasmania and New Zealand, indicating a 
smaller recent extension southward, is all quite in harmony 
with the facts of distribution of the northern flora above 
referred to. 
Supposed Connection of South Africa and Australia . — There 
remains, however, the small amount of direct affinity between 
the vegetation of South Africa and that of Australia, New 
Zealand, and Temperate South America, consisting in all of 
fifteen genera, five of which are confined to Australia and 
South Africa, while several natural orders are better represented 
in these two countries than in any other part of the world. 
This resemblance has been supposed to imply some former land- 
connection of all the great southern lands, but it appears to 
me that any such supposition is wholly unnecessary. The dif- 
ferences between the faunas and floras of these countries are 
too great and too radical to render it possible that any such 
connection should have existed except at a very remote period- 
But if we have to go back so far for an explanation, a much 
simpler one presents itself, and one more in accordance with 
what we have learnt of the general permanence of deep oceans 
and the radical changes that have taken place in the distribu- 
tion of all forms of life. Just as we explain the presence of 
marsupials in Australia and America and of Centetidse in 
