laceae, are represented by only a few
species. Thus, too, we can explain the absence of _all_ the peculiar
Australian Leguminosae; for these were still mainly confined to the great
western island, along with the peculiar Acacias and Eucalypti, which at a
later period spread over the whole continent. It is equally accordant with
the view we are maintaining, that among the groups which Sir Joseph Hooker
enumerates as "keeping up the features of extra tropical Australia in its
tropical quarter," several should have reached New Zealand, such as
Drosera, some Pittosporeae and Myoporineae, with a few Proteaceae,
Loganiaceae, and Restiaceae; for most of these are not only found in
tropical Australia, but also in the Malayan and Pacific islands.

_Tropical Character of the New Zealand Flora Explained._--In this origin of
the New Zealand fauna by a north-western route from North-eastern
Australia, we find also an explanation of the remarkable number of tropical
groups of plants found there: for though, as Sir Joseph Hooker has {501}
shown, a moist and uniform climate favours the extension of tropical forms
in the temperate zone, yet some means must be afforded them for reaching a
temperate island. On carefully going through the _Handbook_, and comparing
its indications with those of Bentham's _Flora Australiensis_, I find that
there are in New Zealand thirty-eight thoroughly tropical genera,
thirty-three of which are found in Australia--mostly in the tropical
portion of it, though a few are temperate, and these may have reached it
through New Zealand[135]. To these we must add thirty-two more genera,
which, though chiefly developed in temperate Australia, extend into the
tropical or sub-tropical portions of it, and may well have reached New
Zealand by the same route.

On the other hand we find but few New Zealand genera certainly derived from
Australia which are especially temperate, and it may be as well to give a
list of such as {502} do occur with a few remarks. They are sixteen in
number, as follows:--

1. Pennantia (1 sp.). This genus has a species in Norfolk Island,
indicating perhaps its former extension to the north-west.

2. Pomaderris (3 sp.). One _species_ inhabits Victoria and New Zealand,
indicating recent trans-oceanic migration.

3. Quintinia (2 sp.). This genus has winged seeds facilitating
migration.

4. Olearia (20 sp.). Seeds with pappus.

5. Craspedia (2 sp.). Seeds with