INTRODUCTION. 
infrequency of rain tends much to give a sombre brown hue to the surface of the ground, which however is 
relieved by the constant verdure of its trees, the peculiar lanceolate form and the pendent position of 
which render them almost shadowless. It is in the neighbourhood of the few rivers which intersect 
the country, and in the lower flats flooded by the waters, Avhen floods occur, that we find the 
vegetation more luxuriant and the trees attaining a far greater size ; the sides of the rivers are moreover 
fringed with CasuanncB and other trees, which, although of large size, never arrive at the altitude of 
the stately Eucalypti, which attain, under favourable circumstances, a size and height which appear 
perfectly incredible. Mr. Backhouse states that one measured by him on the Lopham Road, near Emu 
Bay in Van Diemen's Land, which, " was rather hollow at the bottom and broken at the top, was 49 feet 
round at about 5 feet from the ground ; another that was solid, and supposed to be 200 feet high, was 
41 feet round; and a third, supposed to be 250 feet high, was 55^- feet round. As this tree spread much 
at the base, it would be nearly 70 feet in circumference at the surface of the ground. My companions 
spoke to each other when at the opposite side of this tree from myself, and their voices sounded so distant 
that I concluded they had inadvertently left me, to see some other object, and immediately called to them. 
They in answer remarked the distant sound of my voice, and inquired if I were behind the tree ! When 
the road through this forest was forming, a man who had only about two hundred yards to go, from one 
company of work-people to another, lost himself : he called, and was repeatedly answered ; but getting 
further astray, his voice became more indistinct, till it ceased to be heard, and he perished. The largest 
trees do not always carry up their width in proportion to their height, but many that are mere spars are 
200 feet high." 
A prostrate tree noticed by Mr. Backhouse in the forest near the junction of the Emu River with the 
Loudwater " was 35 feet in circumference at the base, 22 feet at 66 feet up, 19 feet at 110 feet up ; there 
were two large branches at 120 feet; the general head branched off at 150 feet ; the elevation of the tree, 
traceable by the branches on the ground, was 213 feet. We ascended this tree on an inclined plane, formed 
by one of its limbs, and walked four abreast with ease upon its trunk ! In its fall it had overturned another 
168 feet high, which had brought up with its roots a ball of earth 20 feet across." There are other 
remarkable features, which, as they appertain to districts frequently alluded to in the course of the work, 
it becomes necessary to notice, namely the immense deltas formed by the descent of the waters of the 
interior, such as the valley of the Murray near its embouchure into the sea, spoken of as the great Murray 
scrub of South Australia ; this enormous flat of nearly one hundred miles in length by more than twenty in 
breadth is clothed with a vegetation peculiarly its own, the prevailing trees which form a belt down the 
centre consisting of dwarf Eucalypti, while the margins are fringed with shrub-like trees of various kinds. 
Nor must the immense belts of Banksice, which grow on the sand-hills bordering the sea-coast and in some 
parts of the interior, or the districts clothed with grass-trees {Xanthorrhcea^, be passed over unnoticed ; in 
the intertropical regions of Australia, of which at present so little is known, we find, besides the Eucalypti, 
Banksi(s and other trees of the southern coast, dense forests of canes, mangroves, &c. Each of these 
districts has a zoology peculiarly its own : for instance, the Banksi(B are everywhere tenanted by the true 
Meliphagi', \he Eucalypti th^ Ptiloti tmd Tric/wglossi ; the towering fig-trees by the Regent and Satin 
birds ; the palms by the Carpophagcs or fruit-eating Pigeons, and the grassy plains by the ground Pigeons, 
Finches and grass Parrakeets. The circumstance of the boles of the trees being destitute of a thick 
corrugated rind or bark will doubtless account for the total absence of any member of the genus Picus or 
