Brachychiton rupestris – the ‘Queensland Bottle Tree’ or ‘Narrowleaf Bottle Tree’ is native to Queensland and is mostly found in central Queensland, basically from the latitudes of Brisbane to Rockhampton, and generally on the western side of the Great Dividing Range.
In its natural environment the ‘Queensland Bottle Tree’ it is an emergent tree, which means it grows to very tall heights towering over the canopy of the forest below. It can grow up to 3.5 m in diameter at breast height, and can reach some 10 to 25 m (that’s equivalent to a 7 storey building !!!) in height. It occurs naturally in forests dominated by ‘Brigalow’ (Acacia harpophylla), ‘Hoop Pine‘ (Araucaria cunninghamii), and ‘Ooline’ (Cadellia pentastylis) and is always present in the now endangered, central semi-evergreen vine thicket – known as the ‘Bottletree Scrub’ of the Queensland ‘Brigalow Belt’. The root-suckering (i.e. sprouts emanate from the roots) ‘Brigalow’, is a tree that grows some 25 m in height. The word ‘Brigalow’ is thought to be an Aboriginal word referring to various species of wattle.
It is the bulbous trunk of the ‘Queensland Bottle Tree’ that literally resembles a bottle, lead to its common name. Contrary to popular belief, ‘Queensland Bottle Trees’ are not hollow, but have fibrous interiors. Their bottle-shape is due to the water that is stored within the trunk. Interestingly, when clearing the semi-evergreen vine thicket, farmers often leave the ‘Queensland Bottle Tree’ behind as they provide valuable shade for their stock, and, can be used as fodder in times of drought. In desperate times whole trees have been felled to feed stock – exposing the edible pulp inside by removing the bark, thereby providing an energy-rich, but protein-poor, feed.
This water storing capacity classes the ‘Queensland Bottle Tree’ as a succulent. The shedding of leaves, flowering and even secreting from the trunk can vary during times of severe drought and high rainfall.
So, incredulously, Australia has a deciduous succulent amidst its natural flora !!!
Bell shaped, creamy-yellow coloured flowers usually begin to appear in Spring, and are followed by woody, boat-shaped follicles that ripen from November to May. These boat-shaped follicles present in groups of 3 to 5 – each containing 4 to 8 and occasionally up to 12 seeds. The follicles, which are smooth on the outer surface and hairy inside, split along their length to reveal seeds. The seeds, which are somewhat egg-shaped have a smooth surface, and are 6 to 7 mm long x 3.5 to 4.5 mm wide. They are covered by a hairy coating known as the ‘exotesta’.
Aborigines had a variety of uses for the ‘Queensland Bottle Tree’. Firstly is broad canopy provided shelter; the fibre from the trunks of the tree was used to make nets and rope; the Aborigines would eat the roots of young plants; and, drink the secretions from the trunk of the tree.
In the ‘Journal of an Expedition into the Interior of Tropical Australia In Search of a Route from Sydney to the Gulf of Carpentaria’, an excerpt of the journal entry dated 8th May 1846 reads:
” . . . The trunk bulged out in the middle like a barrel, to nearly twice the diameter at the ground, or of that at the first springing of the branches above. These were small in proportion to their great girth, and the whole tree looked very odd. These trees were all so alike in general form that I was convinced this was their character, and not a LUSUS NATUROE. [A still more remarkable specimen of this tree was found by Mr. Kennedy in the apex of a basaltic peak, in the kind of gap of the range through which we passed on the 15th of May, and of which he made the accompanying drawing.] . . . “
Source: Excerpt – ‘Journal of an Expedition by Thomas Mitchell’ – published 1848