1G0 Transactions. — Botany. 



Yet only two of their peculiar plants have migrated to the 

 Kermadec Group. Had the 40 widely distributed species that 

 are common to Norfolk Island and the Kermadecs immigrated 

 directly from Norfolk Island, a larger proportion of the endemic 

 plants of that island would undoubtedly have followed them. 

 Similarly, 7G plants of wide geographical range are found both 

 in Australia and the Kermadec Group ; yet I cannot believe that 

 they have migrated direct from Australia. Surely, if that had 

 been the case, a few, at least, of the many hundred endemic 

 Australian species would have accompanied them. 



We have seen that, out of the 115 species collected in the 

 group, 85 are New Zealand plants. This leaves 30 to be 

 accounted for. Five are peculiar to the group, and 5 more 

 cannot be determined until flowering specimens are obtained. 

 Two are strictly Polynesian species, and the remaining 18 are 

 wide-ranging tropical or sub-tropical plants, many of them 

 common in both hemispheres, and all of them found in Poly- 

 nesia, coming as near to the Kermadecs as Tonga. Probably 

 it is from thence that the Kermadecs have received them. 

 Taking the above data into consideration, it appears to me 

 most probable that the Kermadec Islands have received their 

 plants from two sources : that there have been two opposite 

 streams of colonization — one, much the largest and most 

 important, from New Zealand ; the other, much less con- 

 spicuous, from the Polynesian Islands. 



In coming to this conclusion, it is assumed that the Kermadec 

 Islands have always been isolated from other land masses, or, 

 at any rate, have not formed part of any other land during the 

 tertiary period. But views opposed to this are often held. In 

 endeavouring to solve the difficult and much-debated question 

 of the origin of the New Zealand fauna and flora, it is usually 

 assumed that New Zealand was formerly connected, by way of 

 Norfolk Island and Lord Howe's Island, with North-eastern 

 Australia and New Caledonia ; and, as mentioned at the com- 

 mencement of this paper, a submarine ridge — nowhere much 

 more than 1,000 fathoms in depth, and for a considerable part 

 of the distance much less than that — actually extends in the 

 right direction. This theory has the merit of accounting for 

 two salient features in the natural history of New Zealand. It 

 shows how the ancestors of our struthious birds may have 

 arrived from a country at present inhabited by their nearest 

 living representatives; and it explains, if taken in connection 

 with certain very probable geological changes in Australia, how 

 the very anomalous nature of the relationship of our flora with 

 that of Australia may have arisen, lint it is unnecessary to go 

 into the details of the theory here — they can be found in Mr. 

 Wallace's "Island Life," <>r in Professor Hutton's papers " On 

 the Origin of the New Zealand Fauna and Flora." 



