Plant* in Australia.] INTRODUCTORY ESSAY. lxxxix 
conveys the impression of their generic affinity at least being effected by migration from centres of 
dispersion in one of them, or in some adjacent country. In this case it is widely different. Regarding 
the question from the Australian point of view, it is impossible in the present state of science to recon- 
cile the fact of Acacia* Eucalyptus, Casuarina, Callitris, etc., being absent in New Zealand, with any 
theory of transoceanic migration that may be adopted to explain the presence of other Australian 
plants in New Zealand ; and it is very difficult to conceive of a time or of conditions that could explain 
these anomalies, except by going back to epochs when the prevalent botanical as well as geographical 
features of each were widely different from what they are now. On the other hand, if I regard tin- 
question from the New Zealand point of view, T find such broad features of resemblance, and so 
many connecting links that afford irresistible evidence of a close botanical connection, that I cannot 
abandon the conviction that these great differences will present the least difficulties to whatever theory 
may explain the whole case. I shall again allude to this point after discussing the antarctic and 
European features of Australia. 
Between Norfolk Island and Australia a few small islands rise like specks in the ocean, and 
these, too, tell a tale of distribution. Lord Howe's Island and the Middleton group, in the parallels 
of 28° and 32° south, have both been botanized in by the officers of the ' Herald' (Captain Denham's 
Pacific Exploring Expedition), and their Flora is of an intermediate character between that of Aus- 
tralia, New Zealand, and Norfolk Island, some species being common to each, and the rest, though 
quite distinct, being closely allied to the plants of these countries. 
On the Antarctic Plants 0/ Australia. 
From the geographical position of Australia, no less than from the altitude of its southern 
mountains, it is well placed for the maintenance of those types of vegetation which I have denomi- 
nated Antarctic. These, it must be remembered, are not so called because they really inhabit the 
country of that name beyond the Polar circle, but because in a botanical point of view, no less than 
in position relative to the south temperate Flora, they represent the Arctic Flora. They might 
indeed almost be called alpine plants, for many which are found at the level of the sea in the so-called 
Antarctic islands, also ascend the mountains of more genial latitudes. An alpine vegetation, however, 
in the tropics especially, is supposed to commence only where the forest is replaced by low brush wood ; 
whereas, owing to the uniformity and humidity of the high southern latitudes, an arboreous vegeta- 
tion there encroaches upon the limits of perpetual ice. In the longitude of Cape Horn, on the 
mountains of Fuegia, of the Middle Island of New Zealand, and of Australia, the belt of country 
occupied by low and chiefly herbaceous plants, that intervenes between the arboreous vegetation and 
the extinction of phaenogamic life, is a very narrow one indeed compared with what analogous regions 
the Alps, Andes, Himalaya, or Arctic latitudes present. 
In discussing the antarctic vegetation of Australia, I shall have to adopt a style that appears to 
indicate that this Flora is an immigrant, whereas it may, to a considerable extent, both in Australia 
and elsewhere, consist of altered forms of the plants of that continent, which have migrated from 
* There are no climatic or other r ra 1: sarwhii _" in Ni ■•■ / al . I when introduced 
there. Some introduced Australian plants have already become naturalized in New Zealand ; but upon this point I 
hone to collect more full evidence. 
