replaced by analogous families, as Epacrideæ by Ericeæ; and some tribes which form a considerable part of the Australian peculiarities, as Dilleniaceæ, the leafless Acaciæ and Eucalyptus, are entirely wanting in South Africa.
On the other hand, several of the characteristic South African orders and extensive genera are nearly or entirely wanting in New Holland: thus Irideæ, Mesembryanthemum, Pelargonium, and Oxalis, so abundant at the Cape of Good Hope, occur very sparingly in New Holland, where the South African genera Aloe, Stapelia, Cliffortia, Penæa, and Brunia, do not at all exist. Very few species are common to both countries, and of these the only one which is at the same time peculiar to the Southern hemisphere is Osmunda barbara.
We have not sufficient materials for a satisfactory comparison of the Flora of the higher latitudes of South America with that of the Southern parts of Terra Australis. If, however, we may judge from those at present in our possession, it would seem that the general character of the South American vegetation differs much more from the Australian than this does from that of South Africa. Yet several instances occur of the same or of very nearly related genera, 589] peculiar to the southern hemisphere, which are common to Terra Australis and South America, and which do not exist at the Cape of Good Hope. Thus the Pavonia or Laurelia of Chili has its nearly related genus Atherosperma in Van Diemen's Island; where also a genus that I shall name Tasmania occupies the place of the Wintera of South America, from which it differs chiefly in having a single ovarium; a species of the Araucaria of Chili exists in New Holland as well as in Norfolk Island and New Caledonia; several Lomatiæ are found in South America; a species of Astelia grows in Terra del Fuego; and Goodenia littoralis of the southern shores of Terra Australis is found not only in New Zealand but on the opposite coast of America.
Certain tribes of plants common to South Africa and Terra Australis, and almost equally abundant in both these countries, are either very sparingly produced or cease to exist in South America. Others which abound in South
