Didymocheton gaudichaudianus, commonly known as ivory mahogany, is a species of rainforest tree in the family Meliaceae, native to Malesia, Papuasia, Queensland, and some southwest Pacific islands.
The ivory mahogany is a large tree growing up to in height with a straight trunk up to diameter. The bark is smooth and often has teaspoon-sized depressions in it. Buttress roots are a feature of this tree and may reach up to high and wide.
The very large leaves are produced in whorls and clustered towards the ends of the branches. They are imparipinnate with up to 14 pairs of leaflets, and measure up to in length. This arrangement produces large spherical clusters of foliage (see gallery).
The leaflets are highly asymmetric at the base with one side of the leaf blade wider than the other. They measure up to 30by
The inflorescences are thyrses, about long, and produced in or close to the leaf axils. The flowers are a pale cream or green, 5-merous, with an unpleasant smell. The fruits are capsules about diameter which are covered in fine brown hairs. They have five segments and contain up to 10 seeds about long.
Flowering in Australia occurs from September to January, with fruits ripening around October to February.
This species was first described by Adrien-Henri de Jussieu in 1830. It has been known by many synonyms.
The species epithet was given to honour French botanist Charles Gaudichaud-Beaupré. The former genus name Dysoxylum comes from the Latin dys meaning "bad", and the Ancient Greek xylon meaning "wood", and refers to the unpleasant smell produced by some species.
Didymocheton gaudichaudianus is native to central and eastern Malesia (Christmas Island, Java, the Lesser Sunda Islands, Sulawesi, Maluku Islands, and the Philippines), Papuasia (New Guinea, the Bismarck Archipelago, and the Solomon Islands), Queensland, Australia from the Cape York Peninsula to the Mary River in south east Queensland, and some islands South-West Pacific (Vanuatu, the Samoan Islands, Tonga, and Wallis and Futuna). It grows in lowland rainforest up to 300 metres elevation.