CHAP. xxiTi.] 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 Aiistralia. — 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 w^orld. 

 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 Centetidae in 



