What's a Corymbia?

A New Name for the Bloodwood
and Ghost Gum Eucalypts

Andrew Lyne

5 August 1996

Ken Hill and Lawrie Johnson, two botanists working in the National Herbarium of New South Wales, Sydney, recently published a paper in which they formally recognize the bloodwood and ghost gum groups of the eucalypts as a distinct genus. The new scientific name for this genus is Corymbia.

What this means is that some commonly known bloodwoods such as Eucalyptus maculata, E. gummifera (the Spotted Gum [ illustration ] and Red Bloodwood [ illustration ] [ photo ] familiar to those who visit the south coast) and E. ficifolia (the Red-flowering Gum native to a very restricted area of south-western Western Australia but widely cultivated in other parts of Australia) and the well known ghost gum E. papuana var. aparrerinja (the Ghost Gum of central Australia) now have a new generic name and will be known as Corymbia maculata [ illustration ], C. gummifera [ illustration ] [ photo ], C. ficifolia and C. aparrerinja respectively. (In transferring Eucalyptus papuana var. aparrerinja to Corymbia, Hill and Johnson raised the variety name to specific rank - C. papuana is considered by Hill and Johnson to be confined to Papua New Guinea).

There are 113 recognized species of Corymbia. There are no species of Corymbia in or immediately near the ACT. The bloodwoods closest to Canberra are on the coast - Corymbia eximia (the Yellow Bloodwood) and the previously mentioned C. maculata [ illustration ] and C. gummifera [ illustration ] [ photo ]. The nearest ghost gum, Corymbia tessellaris (Carbeen or Moreton Bay Ash), occurs northwards from northern New South Wales. Most species of Corymbia occur in the northern half of Australia.

The recognition of the bloodwoods and ghost gums as the distinct genus Corymbia has not happened without considerable research. Indeed it was George Bentham in 1867 who first recognized the bloodwoods as a distinct group (albeit within the genus Eucalyptus). In more recent times however, further research has provided greater evidence for recognizing the bloodwoods and ghost gums as a distinct genus. These recent studies have focussed not only upon morphology but also molecular characteristics. Hill and Johnson recognise Corymbia through its possession of a calyptrate calyx (or operculum), unicellular hairs and disjunct adult leaves. More generally, Corymbia can be identified through a combination of characters (shared in some cases with species of Eucalyptus) such as the terminal panicles of urceolate shaped fruits, the wide angle of the leaf venation, and the rough flaky bark although not all species have all these characteristics.

The decision to place the bloodwoods and ghost gums in or out of Eucalyptus has also involved the genus Angophora (the Apples). Angophora is considered to be closely related to Eucalyptus. The problem has been, however, that some species of Eucalyptus (the bloodwoods and ghost gums in this case) are more closely related to Angophora than they are to the rest of Eucalyptus. Therefore it makes little sense from an evolutionary point of view to continue to keep the bloodwoods and ghost gums in Eucalyptus or to maintain Angophora as distinct from Eucalyptus.

As further study brought to light new evidence it became apparent that one of three courses of action could be taken. The first is that Angophora no longer be recognised as a distinct genus and be united with or "sunk" into Eucalyptus. This means for example, that Angophora subvelutina (the Broad-leaved Apple) would be known as Eucalyptus subvelutina. The second is that the bloodwoods and ghost gums be united with or "sunk" into Angophora. This would mean for example that Eucalyptus gummifera would become Angophora gummifera. The third course of action is that the bloodwood and ghost gum species of Eucalyptus be recognized as a distinct genus (Corymbia). In their paper Hill and Johnson have argued for the latter course of action.

In so doing Hill and Johnson made the point that the genera Angophora, Corymbia and Eucalyptus should be commonly referred to as "eucalpyts" as they are such close relatives and the distinctions between them fine. (Angophora species are also commonly referred to as Apples). Other common names of course will not be changed - whether the eucalypt was once a Eucalyptus gummifera and is now a Corymbia gummifera, a Red Bloodwood [ illustration ] [ photo ]is still a Red Bloodwood [ illustration ] [ photo ].

The following list of references may be of interest to readers who wish to find out more about the taxonomy of the eucalypts.

Bentham, G. (1867). Flora Australiensis: a Description of the Plants of the Australian Territory. Vol. 3 Myrtaceae to Compositae. 704 pp. Lovell Reeve & Co., London.

Brooker, M.I.H. and Kleinig, D.A. (1994). Field Guide to Eucalypts. Vol. 3. Reed International Books Australia Pty Limited trading as Inkata Press.

Hill, K.D. and Johnson, L.A.S. (1995). Systematic studies in the eucalypts. 7. A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea 6(2-3): 185-504.

Johnson, L.A.S. and Briggs, B.G. (1983). Myrtaceae. In Morley, B.D. and Toelken, H.R. (eds). Flowering Plants in Australia. Rigby Publishers, Adelaide.

Pryor, L.D. and Johnson, L.A.S. (1971). A Classification of the Eucalypts. Australian National University Press, Canberra.

Udovicic, F., McFadden, G.I. and Ladiges, P.Y. (1995). Phylogeny of Eucalyptus and Angophora based on 5S rDNA spacer sequence data. Molecular Phylogenetics and Evolution 4(3): 247-256.

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An Introduction to the Eucalypts

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Updated by Andrew Lyne

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