506 ISLAND LIFE 



PART II 



Cyperacese and Graminese — with the high proportion in 

 each case of one-fourth. These nine are the most 

 important New Zealand orders which contain species 

 common to that country and Australia and confined to 

 them ; and the marked correspondence they show between 

 high specialisation and want of specific identity, while the 

 generic identity is in all cases approximately equal, points 

 to the conclusion that the means of diffusion are, in almost 

 all plants ample, when long'periods of time are concerned, 

 and that diversities in this respect are not so important 

 in determining the peculiar character of a derived flora, as 

 adaptability to varied conditions, great powers of multi- 

 plication, and inherent vigour of constitution. This point 

 will have to be more fully discussed in treating of the 

 origin of the Antarctic and north temperate members of 

 the New Zealand flora. 



Summary and Conclusion on the New Zealand Flora, — Con- 

 fining ourselves strictly to the direct relations between the 

 plants of New Zealand and of Australia, as I have done in 

 the preceding discussion, I think I may claim to have 

 shown that the union between the two countries in the lat- 

 ter part of the Secondary epoch at a time when Eastern 

 Australia was widely separated from Western Australia (as 

 shown by its geological formation and by the contour of 

 the sea-bottom) does sufficiently account for all the main 

 features of the New Zealand flora. It shows why the 

 basis of the flora is fundamentally Australian both as re- 

 gards orders and genera, for it was due either to a direct 

 land connection or a somewhat close approximation 

 between the two countries. It shows also why the great 

 mass of typical Australian forms are unrepresented, for the 

 Australian flora is typically western and temperate, and New 

 Zealand received its immigrants from the eastern island 

 which had itself received only a fragment of this flora, and 

 from the tropical end of this island, and thus could only 

 receive such forms as were not exclusively temperate in 

 character. It shows, further, why New Zealand contains 

 such a very large proportion of tropical forms, for we see 

 that it derived the main portion of its flora directly from 

 the tropics. Again, this hypothesis shows us why, though 



