4 
The described portion of the Tertiary Flora of Australia forms no 
exception to this rule. A glance at the accompanying table will show that 
it contains, not only many genera which occur also in the Tertiary Floras of 
Europe, North America, and Northern Asia, but, in general, representatives 
of the floral regions. These embrace Filices, Coniform, and all the principal 
classes of Dicotyledon*. The genera Myrica, Betula , Alnus , Quercus, Fay us, 
and Salix, are characteristic of the European and North American floras; 
the Castanopsis, Cinnamomum, Tabcnnemontana, Fremna, Elceocarpus, and 
Balbergia, point to East India and China ; Magnolia especially to the 
Avarmer parts of North America; Bombax to tropical America; Knightia 
and Coprosma .to Oceania. A comparatively feAV genera, such as Lomatia, 
Banhsia, Ceratopetalum, Fittosporum, and Eucalyptus, are representatives of 
the existing flora of Australia*. Of the species, hoAvever, not one is identical 
with any species belonging to the Tertiary Floras named ; but thirty-four 
species are more or less allied to species in those floras ; and lienee it follows 
that the Tertiary Flora of extra-tropical Australia is closely related to the 
Tertiary Floras of Europe, North America, and the Arctic Regions. Compared 
with the present flora of Australia, hoAvever, the Tertiary Floras named 
appear strikingly different ; yet, inasmuch as they scarcely differ among tlieni- 
selves, Ave may, eliminating unimportant differences, consider them as forming 
together the common origin of all the extra-tropical floras of the earth. 
The combination of the Tertiary floral-elements into a common 
original flora may be traced even as far as the grouping of the species of a 
genus. The present flora of Australia is devoid of the genus Quercus. In 
its Tertiary Flora, on the other hand, Ave can point to five species, of which 
tivo are analogous to those found in the East Indies, one to the Oceanian 
Q. phi lippinensis, one to the Q. castanecefolia of the Caucasus and Northern 
Persia, and one to the Q. stellata of North America. 
The Tertiary Floras of the tropics, to judge from the certainly very 
scanty material at present available, appear to differ from the Tertiary Floras 
of the extra-tropical regions of the earth, in so far that the first are more 
closely allied to the living floras than the latter. No doubt this greater 
similarity between the Tertiary and the existing tropical floras is owing to 
the fact that, in the interval between the Tertiary Epoch and the present 
age, the climatic conditions of the tropics have remained comparatively 
unaltered. At the same time, the analogy is very striking between the three 
* On a further exploration of the Tertiary Flora of Australia, the number of Australian genera will, no 
doubt, be considerably increased ; but as this will also most likely be the case with the non-Australian genera 
no essential alteration in the mixed character of the lloral elements need be looked for. 
