27 
ductory Essay to the Flora Tasmania?*), does not go so far as this, 
although he, too, says, “ that 216 or one-fourth of the New Zealand 
Phrenogams are natives of Australia, and of these 115 species are con¬ 
fined to these two countriesand, “ that of the 115 specimens pecu¬ 
liar to Australia and New Zealand, only 26 belong to genera peculiar 
to those countries, and only 6 to the long list of Australian genera 
which contain upwards of 20 species each.” Nevertheless it is believed 
that this comparison will bo very materially altered, when the whole of 
the Flora of New Zealand (and tho many other Polynesian Islands) 
shall be fully known. Alroady, since the publication of tho Flora 
Novce-Zelandue , have many new species been discovered in New Zea¬ 
land, particularly in the Middle Island; where too, are sevoral South 
American genera hitherto not detected in the North Island, (as Donat ia, 
Rostkouia, Gaimard'ia , &c.), and, consequently, not referred to in this 
Essay. And of thoso 26 species belonging to genera at proscnt only 
common to Australia and New Zealand, may it not reasonably bo ex¬ 
pected, that some of these will be also found in the many unexplored 
sub-tropical islands ? Again, seeing that the striking characteristic 
Australian genera (while found in Tasmania) are wholly wanting in 
Now Zealand; and that tho characteristic New Zealand genera are 
also (as such) wanting in Australia; is it not evident, that it is not so 
much from what is (the positive), as from -what is not (the negative), 
that tho better comparison can in this caso be drawn, and the truer 
Botanical affinity deduced ? [Reviewing, then, what is already known 
of New Zealand and Southern insular Botany, and looking forward 
expectingly to future kindred revelations, it is not unreasonably be¬ 
lieved, that the Botany of the New Zealand group will bo found to bo 
peculiar, and not so closely related with tho nearest main-land (Aus- 
lia), as with many other small islands, and therefore, forming with 
them a Southern Botanical insular region, of which Now Zealand is 
probably about the existing centre. 
22. In bringing this necessarily imperfect outlino of the Botanical 
Geography of the North Island to a closo, many such thoughts as the 
following present themselves for consideration:— 
Is there a natural law affecting the (lissemiuation of plants ? 
Is a climatic, or geognostic, difference, of greater value than a mere 
geographical one ? 
* Page lxxxviii.:—An admirable work, well worthy tho serious study of every student of 
New Zealand Botany. 
