Plants 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 the 

 question from the New Zealand point of view, I 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. 



§ 10. 

 On the Antarctic. Plants of 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 brushwood ; 

 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 phsenogamic 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 reasons against these genera flourishing in New Zealand when introduced 

 there. Some introduced Australian plants have already become naturalized in New Zealand ; but upon this point I 

 hope to collect more full evidence. 



