Ficus macrophylla, commonly known as the Moreton Bay Fig, is a large evergreen banyan tree of the Moraceae family that is a native of most of the eastern coast of Australia, from the Atherton Tableland in the north to the Illawarra in New South Wales, and Lord Howe Island. Its common name is derived from Moreton Bay in Queensland, Australia. It is best known for its beautiful buttress roots, which are also known for damaging municipal sidewalks.
Ficus macrophylla is a strangler fig; seed germination usually takes place in the canopy of a host tree and the seedling lives as an epiphyte until its roots establish contact with the ground. It then enlarges and strangles its host, eventually becoming a freestanding tree in its own right. Individuals may reach 60 m (200 ft) in height. Like all figs, it has an obligate mutualism with fig wasps; figs are only pollinated by fig wasps, and fig wasps can only reproduce in fig flowers.
It is widely used as a feature tree in public parks and gardens around the world in warmer climates such as California, Portugal, Sicily and of course Australia. Old specimens can reach tremendous size. Its aggressive root system precludes its use in all but the largest private gardens.
The generally used common name is Moreton Bay Fig, after Moreton Bay in southern Queensland, although it is found elsewhere. The term has also been mistakenly generalised to other fig species in Australia. An alternate name, Black Fig, is derived from the dark colour of the ageing bark.
With over 750 species, Ficus is one of the largest angiosperm genera. Based on morphology, English botanist E. J. H. Corner divided the genus into four subgenera; later expanded to six. In this classification, the Moreton Bay fig was placed in subseries Malvanthereae, series Malvanthereae, section Malvanthera of the subgenus Urostigma. In his reclassification of the Australian Malvanthera, Dixon altered the delimitations of the series within the section, but left this species in series Malvanthereae.
In 2005, Cornelis Berg completed Corner's treatment of the Moraceae for the Flora Malesiana; the completion of that work had been delayed since 1972 as a result of disagreements between Corner and C. J. J. G. van Steenis, editor of the Flora Malesiana. Berg combined sections Stilpnophyllum and Malvanthera into an expanded section Stilpnophyllum. This left the Moreton Bay fig in subsection Malvanthera, section Stilpnophyllum.
Based on DNA sequences from the nuclear ribosomal internal and external transcribed spacers, Nina Rønsted and colleagues rejected previous subdivisions of the Malvanthera. Instead, they divided section Malvanthera into three subsections - Malvantherae, Platypodeae and Hesperidiiformes. In this system, the Moreton Bay fig is in the new subsection Malvantherae.
The Moreton Bay Fig is an evergreen tree that can reach heights of 60 m (200 ft). The trunk can be massive, with thick, prominent buttressing. The bark is grey and rough. It is monoecious; each tree bears functional male and female flowers. As implied by its specific epithet, it has large , elliptic, leathery, dark green leaves, 15–30 cm (6-12 in) long. The figs are 2–2.5 cm (0.75–1 in) in diameter, turning from green to purple with lighter spots as they ripen; ripe fruit may be found year round. Though edible, they are unpalatable.
The characteristic "melting" appearance of the Moreton Bay fig is due to its habit of dropping aerial roots from its branches which on reaching the ground thicken into supplementary trunks which help to support the great weight of its crown.
It is a rainforest plant and in this environment more often grows in the form of an epiphytic strangler vine than that of a tree. When its seeds land in the branch of a host tree it sends aerial, 'strangler' roots down the host trunk, eventually killing the host and standing alone.
Its roots are surface feeding and it is therefore quite susceptible to the compacting of earth around its trunk, which is why in many parks and gardens these trees are fenced off. It is water hungry and like many Australian trees should not be planted in urban environments where its roots may damage piping, nor in areas where water is scarce.
Figs have an obligate mutualism with fig wasps, (Agaonidae); figs are only pollinated by fig wasps, and fig wasps can only reproduce in fig flowers. Generally, each fig species depends on a single species of wasp for pollination. The wasps are similarly dependent on their fig species in order to reproduce. The Moreton Bay fig is pollinated by the fig wasp Pleistodontes froggatti.
Although their root buttressing is a potential feature, the Moreton Bay Fig is poorly suited to bonsai as their large leaves do not reduce much in size and they have long internodal growth. It is can be used as an indoor plant in medium to brightly-lit indoor spaces.