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APPENDIX. [ Botany of Terra, Australis. 
There are some other Australian natural families of plants to which, either 
as containing distinct and peculiar genera, or a considerable number of spe- 
cies, similar remarks might be extended ; but I have already exceeded the 
limits prescribed for the present essay, which I shall therefore conclude with 
a few general observations, chiefly deduced from the facts previously stated, 
and with a very slight comparison of the vegetation of Terra Australis with 
that of other countries. 
I have formerly remarked that nearly half the Australian species of 
plants, at present known, have been collected in a parallel included be- 
tween 33° and 35° S. latitude ; and it appears, from the preceding obser- 
vations on the several natural orders, that a much greater proportion of the 
peculiarities of the Australian Flora exist in this, which I have therefore 
called the principal parallel] and that many of them are even nearly con- 
fined to it. But these peculiarities exist chiefly at its western and eastern 
extremities, and are remarkably diminished in that intermediate part which 
is comprehended between 133° and 138° E. long. 
From the principal parallel most of the characteristic tribes diminish 
in number of species as well as of individuals, not, however, equally in 
both directions, but in a much greater degree towards the equator. Jn 
Van Diemen’s Island the same general aspect of vegetation is retained ; 
but of the natural orders forming the peculiar character of the principal 
parallel several are very much reduced, while none are augmented in 
numbers ; and the only tribes which enter in nearly the same proportion 
into the composition of its Flora are Eucalyptus , the Leafless Acacia ? and, 
perhaps, Epacrideie. Within the tropic, at least on the East coast, the 
departure from the Australian character is much more remarkable, and an 
assimilation nearer to that of India than of any other country takes place. 
Several of the peculiar orders and extensive genera of the principal parallel 
are here exceedingly diminished, and none remain in nearly equal propor- 
tion except Eucalyptus and the Leafless Acacice. 
These two genera are not only the most widely diffused, but, by far, 
the most extensive in Terra Australis, about 100 species of each having 
been already observed ; and if taken together and considered with respect 
