CHAP. XXII.] 



THE FLORA OF NEW ZEALAND. 



4G1 



temperate South American, many being also Antarctic or 

 European; while others again are especially tropical or Poly- 

 nesian ; yet undoubtedly a larger proportion of the Natural 

 Orders and genera are common to Australia than to any other 

 country, so that we may say that the basis of the flora is 

 Australian with a large intermixture of northern and southern 

 temperate forms and others which have remote world-wide 

 affinities. 



I General features of the Australia7i Flora and its prolalle 

 Origin. — Before proceeding to point out how the peculiarities 

 of the New Zealand flora may be best accounted for, it is 

 necessary to consider briefly what are the main peculiarities 

 of Australian vegetation, from which so important a part of 

 that of New Zealand has evidently been derived. 



The actual Australian flora consists of two great divisions — 

 a temperate and a tropical, the temperate being again divisible 

 into an eastern and a western portion. Everything that is 

 characteristic of the Australian flora belongs to the temperate 

 division (though these often overspread the whole continent), 

 in which are found almost all the remarkable Australian types 

 of vegetation and the numerous genera peculiar to this part of 

 the world. Contrary to what occurs in most other countries, the 

 tropical is far less rich in species and genera than the temperate 

 region, and what is still more remarkable it contains com- 

 paratively few peculiar species, and very few peculiar genera. 

 Although the area of tropical Australia is about equal to that 

 of the temperate portions, and it has now been pretty well 

 explored botanically, it has less than half as many species.^ 



1 Sir Joseph Hooker informs me that the number of tropical Australian 

 plants discovered within the last twenty years is very great, and that the 

 statement as above made may have to be modified. Looking, however, at 

 the enormous disproportion of the figures given in the "Introductory 

 Essay" in 1859 (2,200 tropical to 5,800 temperate species) it seems hardly 

 possible that a great difference should not still exist, at all events as 

 regards species. Sir Joseph Hooker also doubts the generally greater 

 richness of tropical over temperate floras which I have taken as almost an 

 axiom. He says: Taking similar areas to Australia in the Western 

 World, e.g.^ tropical Africa N. of 20° as against temperate Africa and 

 Europe up to 47°- — I suspect that the latter would present more genera and 



