Sandpaper fig

Sandpaper fig

Of the forty-two species of fig found in Australia, three have the common name of sandpaper fig due to the rough texture of the leaves. All grow along the east coast and top end of Australia in gullies, along creeks and in rainforest. Ficus coronata, so named because of the crown-like ring of bristles around the apex of the fruit, is the most common of the three.

Unlike other native figs, the sandpaper fig is a medium tree, usually growing between 6 and 12 m tall (the latter under ideal rainforest conditions) with a weeping growth habit. It is adapted to a range of habitats – rocky gullies, creeks, open country and rainforest – and will grow in full sun or low light and in poor soils. This tree is, however, frost sensitive in its early years. Although it has a smaller root system than other figs, the sandpaper fig should be planted a least 5 m away from plumbing and buildings. It can be pruned to maintain an elegant specimen tree or as a hedge. If space is a limitation, the sandpaper fig can be grown in pots and makes an interesting bonsai. This is a low maintenance, hardy, drought-resistant plant that produces edible fruit that can be eaten fresh, dried or cooked into cakes, biscuits, jams or sauces.

Like all figs, the sandpaper fig has a fascinating reproductive cycle. The green, immature ‘fruit’ which emerges directly from the trunk or branches, is really a hollow, expanded stalk with a small opening (ostiole) at the apex. The flowers are found on the inside of this structure. For the fruit to develop, the flowers have to be pollinated and this involves an obligatory co -dependent relationship with a wasp specific to the fig species. The female wasp, carrying pollen from its host fig, enters the ostiole and deposits her eggs inside the flowers whilst coincidentally pollinating them. She then forces her way out and dies. Pollination stimulates development of the fruit during which time the wasp eggs hatch into larvae that eventually pupate. The emergent adult males mate with the female pupae, and each burrows out of the fig (providing a funnel for the pollen-laden females to escape) and then dies. This hole reduces the carbon dioxide level inside the fruit and stimulates ripening. And so, the cycle continues. The fig produces an enzyme (ficain) that digests any trapped dead wasps, the resulting nutrients being absorbed to assist in ripening the fruit and seeds.

Sandpaper figs have been important to First Nations people. The leaves were used by women to remove the hairs on their thigh to enable fibres to be rubbed painlessly to make string. The men used the leaves to smooth weapons and wooden implements. The fibres of the inner bark were spun into string for fishing and animal traps. The fruit was eaten when ripe after removing the fine, surface hairs whilst the milky latex was used to treat warts and ringworms. The wood was used in tool making and for fire.

The sandpaper fig is also an important provider for a variety of wildlife. It is the host plant for the caterpillars of the purple moonbeam butterfly. Lizards, several birds (including the figbird, green catbird, olive-backed oriole and topknot pigeon) and the grey-headed flying fox feed on the fruit.

Ficus coronata
Ficus coronata. Photograph by Heather Knowles.
Ficus coronata
Ficus coronata. Photograph by Heather Knowles.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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