x distinct rails of the genus Ocydromus, as well as the numerous
species in some of the peculiar New Zealand genera of plants, which seem
less likely to have been developed in a single area than when isolated, and
thus preserved from the counteracting influence of intercrossing.

In the present state of our knowledge these seem all the conclusions we can
arrive at from a study of the New Zealand fauna; but as we fortunately
possess a tolerably {486} full and accurate knowledge of the flora of New
Zealand, as well as of that of Australia and the south temperate lands
generally, it will be well to see how far these conclusions are supported
by the facts of plant distribution, and what further indications they
afford us of the early history of these most interesting countries. This
inquiry is of sufficient importance to occupy a separate chapter.

* * * * *

{487}

CHAPTER XXII

THE FLORA OF NEW ZEALAND: ITS AFFINITIES AND PROBABLE ORIGIN

Relations of the New Zealand Flora to that of Australia--General
Features of the Australian Flora--The Floras of South-eastern and
South-western Australia--Geological Explanation of the Differences of
these two Floras--The Origin of the Australian Element in the New
Zealand Flora--Tropical Character of the New Zealand Flora
Explained--Species Common to New Zealand and Australia mostly Temperate
Forms--Why Easily Dispersed Plants have often Restricted
Ranges--Summary and Conclusion on the New Zealand Flora.

Although plants have means of dispersal far exceeding those possessed by
animals, yet as a matter of fact comparatively few species are carried for
very great distances, and the flora of a country taken as a whole usually
affords trustworthy indications of its past history. Plants, too, are more
numerous in species than the higher animals, and are almost always better
known; their affinities have been more systematically studied; and it may
be safely affirmed that no explanation of the origin of the fauna of a
country can be sound, which does not also explain, or at least harmonise
with, the distribution and relations of its flora. The distribution of the
two may be very different, but both should be explicable by the same series
of geographical changes.

The relations of the flora of New Zealand to that of Australia have long
formed an insoluble enigma for {488} botanists. Sir Joseph Hooker, in his
most instruct