Commonly known as the small-leaved fig, Ficus obliqua was described by German naturalist Georg Forster in 1786 based on type material collected in Vanuatu.
The specific epithet is the Latin adjective obliquus, meaning "oblique", although the attribute it refers to is unclear.
Joseph Banks and Daniel Solander collected and named Ficus virginea from Booby Island in 1770, which was synonymised with F. obliqua by William Philip Hiern in 1901.
puberula was found to be more distantly related to obliqua than rubiginosa and hence has been reclassified as a separate species, Ficus brachypoda.
[8] In a study published in 2008, Nina Rønsted and colleagues analysed the DNA sequences from the nuclear ribosomal internal and external transcribed spacers (ITS and ETS), and the glyceraldehyde-3-phosphate dehydrogenase (G3pdh) region, in the first molecular analysis of the section Malvanthera.
[11] It has smooth thin grey bark with lighter-coloured lenticels, and a buttressed trunk, which may reach 3 m (9.8 ft) in diameter.
[6] F. obliqua can be distinguished by its smaller fruit on shorter stalks and its glabrous (hairless) leaves; in addition, the petioles have ascending hyaline hairs.
[15] Ficus obliqua occurs from Mount Dromedary (36° S) in southern New South Wales northwards along the coast and Great Dividing Range to the tip of Cape York Peninsula in north Queensland.
Outside Australia it occurs on New Guinea and offshore islands,[13] through eastern Indonesia to Sulawesi in the west and east into the southwestern Pacific,[16] where it is found in New Caledonia,[17] Fiji, Tonga, Samoa and Vanuatu.
[12] The double-eyed fig parrot (Cyclopsitta diophthalma) eats the fruit of Ficus obliqua, steadily depositing fruity detritus on the ground.
[19] The rainbow lorikeet (Trichoglossus moluccanus) is another parrot that consumes the fruit and disperses the seeds;[5] other Australian bird species include the southern cassowary (Casuarius casuarius),[4] brown cuckoo-dove (Macropygia phasianella), rose-crowned fruit dove (Ptilinopus regina), wompoo fruit dove (P. magnificus), wonga pigeon (Leucosarcia melanoleuca), topknot pigeon (Lopholaimus antarcticus), silvereye (Zosterops lateralis), pied currawong (Strepera graculina), black-faced cuckoo-shrike (Coracina novaehollandae), olive-backed oriole (Oriolus sagittatus), Australasian figbird (Sphecotheres vieilloti), green catbird (Ailuroedus crassirostris), regent bowerbird (Sericulus chrysocephalus), satin bowerbird (Ptilonorhynchus violaceus), and Lewin's honeyeater (Meliphaga lewinii).
[25] The thrips species Gynaikothrips australis feeds on the underside of new leaves of F. obliqua, as well as F. rubiginosa and F. macrophylla.
The females of the new generation collect pollen from the male flowers, which have matured by this point, and leave to visit other syconia and repeat the process.
A field study in Brisbane found that F. obliqua trees often bore both male and female syconia at the same time—this could be beneficial for reproduction in isolated populations, such as those on islands.
The same study found a slightly reduced number of male phase syconia in winter, thought due to increased mortality of the wasp pollinator in cooler months.
[14] The animals that eat the figs disperse the seeds, which then germinate and grow on other plants (epiphytes) or on rocks (lithophytes).
[12] Ficus obliqua is an elegant shade tree for parks or fields, and is adaptable to differing soils.
[11] Although it is much less used in bonsai than F. rubiginosa,[31] F. obliqua is well-suited for use in the medium; its small leaves and trunk's propensity to thicken give it attributes optimal for a tree 10–80 cm (3.9–31.5 in) in height.
It is seen in bonsai nurseries mainly in the Brisbane area, where it is a locally common species, and is very highly regarded by at least one proponent, Bradley Barlow.
[36] Its white sap has been used for painful or swollen joints and limbs or boils, or diluted with water and drunk to improve breast milk.
Liquid extracted from the root bark has been used for headaches or, when diluted, to improve health after childbirth, and the leaves are applied to venereal lesions.