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Corymbia torelliana (F.Muell.) K.D.Hill & L.A.S.Johnson
(Myrtaceae – the gum family)
synonym: Eucalyptus torelliana F. Muell. 1877
pronounced: yoo-kuh-LIP-tuss tor-RELL-ee-AR-nuh
common name: Cadaghi Gum
Corymbia is from the Greek κορυμβος (korymbos), cluster, referring to the way the flowers are produced in corymbs; torelliana is named for Otto Torell (1828–1900), Swedish naturalist, geologist and explorer. The Cadaghi of the common name is more difficult. The word has a number of other ways of being spelt, one of the most common being Cadagi. This is the name of a property in the hinterland of the Cairns Northern Beaches, and that may possibly be the origin of the name.
This eucalypt is a native of the Atherton Tableland, North Queensland. It was a popular garden plant about 20 years ago, especially in the Brisbane area, but it was susceptible to sooty mould and developed an unhealthy appearance in gardens. As a result, it lost its appeal and is no longer grown there, although there are many still remaining in established gardens; but unfortunately it has now spread into bushland around Brisbane at a rampant rate. Because it has large leaves with a canopy denser than that of the surrounding vegetation, it creates heavy shade over the understorey of local species, and inhibits their growth. In this way, the Cadaghi Gum has a significant capacity to change the nature of the forests around Brisbane. In the Toowoomba area, it has been declared a noxious weed. Here on the island, there is a line of these trees in private gardens on the Horseshoe Bay road.
This is a dense shade tree with an irregular crown, growing to 25 m or more. It has fibrous bark, which may be tessellated, on the base of the trunk, followed by smooth bark which is usually greenish or greyish green,but after being exposed for some time, it turns grey in colour. The twigs are slender and reddish. The mature leaves are alternate, but the juvenile ones may be opposite. The juvenile leaves are simple, variable in shape but usually ovate, up to 18 cm long, with a wavy margin, green above or with a pink tint, generally pubescent. The leaf is wider than those of most other eucalypts, in keeping with the generally wide leaves of the other rainforest species of trees among which they grow. The adult leaves are alternate (8–16 cm long by 1.5–6 cm wide) have lateral veins at a wide angle to the midrib, and glands are visible near the leaf margins. The adult leaves are ovate, alternate, with an acute apex and a cuneate or oblique base.
The attractive flowers with numerous stamens are borne in large creamy white clusters, appearing locally in July – August. The fruits are large and nearly round woody capsules, with many tiny seeds; these are mainly spread by humans, birds, gravity, and the wind. Some are also moved by stingless native bees.
The timber is very stable, highly figured, a rich bronze-gold colour, with a very pretty grain that can have a bit of a wave in it, very hard, and finishes beautifully. It does have a great deal of sapwood which is termite susceptible unless treated. It was once a popular timber tree, but is little used now due to its relative rarity.
Corymbia torelliana attracts various sap-sucking insects, and the honeydew they exude is attacked by a sooty mould. As the honeydew drifts on the breeze, the sooty mould will cover any buildings within 100 m of the tree. Houses can be covered by this black mould. I did not see any mould present on the local specimens.
The larvae of Ardozyga nyctias use this tree as a food plant.
Photographs taken in Horseshoe Bay 2009
Page last updated 2nd November 2016