G. M. Taomson.—On the Origin of the New Zealand Flora. 501 
introduced, and it is by this spreading north from a common centre that we 
must account for so many species which are found both here and in the 
Tasmanian and Australian alps. Why some species should become modi- 
fied and others remain persistent, I do not know. Thus our Fuchsias 
and pepper trees are distinct from the species found in South America, 
though certainly derived from that region, while our tutu plants (Coriaria 
angustifolia and thymifolia) are identical with others found on the Andes. 
| We cannot work out these problems with our present information, for the 
i necessary factors are wanting. 
| The northern extension of New Zealand indicated by Mr. Wallace as 
existing formerly, would bring it into very close proximity to North-eastern 
Australia, which may then have been in form of a long, narrow island, run- 
ning nearly north and south; and also close to extensive sub-continental 
| areas, of which only the remains are now left in the Polynesian Islands. 
_ And not only did those forms which are common to New Zealand and 
Australia, and New Zealand and Polynesia, find their way thus southwards, 
but it was probably by this chain that the plants of European and Asiatic 
affinity now found in our islands were introduced. But it was only 
at a much later period that an upheaval took place of the compara- 
tively shallow seas separating the eastern and western portions of Aus- 
tralia; and that those forms now so characteristic of Australia, and which 
had been long developing under the peculiar conditions of their isolation 
in the western portion, overran the whole continent and stamped their 
features so markedly on its flora. And it is to this explanation that we 
must look in accounting for the presence of so many plants in New Zealand 
and Eastern Australia which are not found at all in Western Australia. A 
few specially Australian plants may have at later periods found their way 
into this colony, as the prevalent winds here are from the west, and birds 
_ re still found which have apparently strayed across the intervening expanse 
_ Of ocean, but their number must be almost inappreciable, and cannot affect 
- the general result. 
While many of the immigrants thus introduced may have transmitted 
their characters almost unaltered through many successive generations, so 
a that we still rank their descendants as belonging to species yet to be 
. found outside New Zealand, others gave rise to variations and sports, and 
2 course of time the accumulation of these variations has amounted to 
Specific importance, and in some eases even to generic. 
& T believe that some ee eS ae : 
account for the present geographical distri of our flora, but it 
Cores oes rar ange eae — 
