Natural Orders.] AT I ENDIX. 
547 
however, coniine myself to a few remarks on the distribution of the most 
extensive genera. 
Of Eucalyptus alone nealy 100 species have been already observed, 
most of these are trees, many of them ol great and some of enormous dimen- 
sions. Eucalyptus globulus of Eabillardiere and another species peculiar to 
the south end of Van Diemen’s Island, not unfrequently attain the height of 
150 feet, with a girth near the base ol from 25 to 40 leet. In the colony ol 
Port Jackson there are also several species of great size, but none equal to 
those of Van Diemen’s Island : and no very large trees of this genus were 
seen cither on the south coast or in the equinoctial part of New Holland. 
Mr. Caley has observed within the limits of the colony of Port Jackson 
nearly 50 species of Eucalyptus, most of which are distinguished, and have 
proper names applied to them, by the native inhabitants, who Irom differ 
ences in the colour, texture, and scaling of the bark, and in the ramifica- 
tion and general appearance of these trees, more readily distinguish them 
than botanists have as yet been able to do. Eucalyptus, although so gene- 
rally spread over the whole of Terra Australis, and so abundant as to form 
at least four-fifths of its forests, is hardly found beyond this country. I am 
acquainted with one exception only, in an additional species which is said 
to be a native of Amboyna. 
Next to Eucalyptus in number, is the beautiful genus Melaleuca, of 
which upwards of 30 Australian species have already been observed, ex- 
clusive of Tristania, Calothamnus, Beaufortia, and an unpublished genus 
which I separate from it. The maximum of Melaleuca exists in the prin- 
cipal parallel, but it declines less towards the south than within the tropic, 
where its species are chiefly of that section which gradually passes into 
Callistemon, a genus formed of .those species of Metros ideros that have 
inflorescence similar to that of Melaleuca, and distinct elongated filaments. 
With the exception of two species of this section, namely, Melaleuca Leu- 
cadendron, and M. Cajeputi, the genus Melaleuca appears to be confined 
to Terra Australis. 
Lcptospermum, of which, nearly 30 Australian species have been 
observed exists also in New Zealand and in the Moluccas. In Terra Au- 
sfralis its’ maximum is decidedly in the principal parallel, and like Melaleu- 
ca. it is much more abundant in the southern regions than within the tropic. 
