Eucalyptus sideroxylon

Eucalyptus sideroxylon, commonly known as mugga ironbark,[2] or red ironbark[3] is a small to medium-sized tree that is endemic to eastern Australia. It has dark, deeply furrowed ironbark, lance-shaped adult leaves, flower buds in groups of seven, white, red, pink or creamy yellow flowers and cup-shaped to shortened spherical fruit.

Mugga ironbark, red ironbark
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Myrtales
Family:	Myrtaceae
Genus:	Eucalyptus
Species:	E. sideroxylon
Binomial name
Eucalyptus sideroxylon A.Cunn. ex Woolls[1]
E. sideroxylon, field distribution

flower buds and flowers - white form

flowers - red form

Description

Eucalyptus sideroxlylon is a tree that typically grows to a height of 25–35 m (82–115 ft) and forms a lignotuber. The bark is dark grey to black, deeply furrowed ironbark on the trunk and larger branches, smooth white to grey on the thinnest branches. Young plants and coppice regrowth have lance-shaped to oblong or linear leaves that are 30–110 mm (1.2–4.3 in) long and 5–35 mm (0.20–1.38 in) wide. Adult leaves are lance-shaped, the same shade of green on both sides, 50–140 mm (2.0–5.5 in) long and 10–40 mm (0.39–1.57 in) wide tapering to a petiole 5–25 mm (0.20–0.98 in) long. The flower buds are arranged in leaf axils on an unbranched peduncle 7–29 mm (0.28–1.14 in) long, the individual buds on pedicels 3–15 mm (0.12–0.59 in) long. Mature buds are oval or diamond-shaped, 6–15 mm (0.24–0.59 in) long and 4–6 mm (0.16–0.24 in) wide with a conical to beaked operculum. Flowering occurs from April to December and the flowers are white, red, pink or creamy yellow. The fruit is a woody cup-shaped to shortened spherical capsule 5–11 mm (0.20–0.43 in) long and 5–10 mm (0.20–0.39 in) wide with the valves below the level of the rim.[2][4][5][6][7]

Taxonomy and naming

Allan Cunningham recorded the name Eucalyptus sideroxylon in Thomas Mitchell's 1848 Journal of an Expedition into the Interior of Tropical Australia but did not provide a description of the plant. The first formal description of the species was published in 1887 by William Woolls in Proceedings of the Linnean Society of New South Wales.[8][9] The specific epithet (sideroxylon) is derived from the ancient Greek words sidēros (σίδηρος), meaning "iron" and xylon (ξύλον), meaning "wood".[10]

Two subspecies of E. sideroxylon are accepted by the Australian Plant Census as at December 2019:

• Eucalyptus sideroxylon subsp. improcera A.R.Bean[11] is a small, stunted tree and has shorter, wider leaves than the autonym and longer flower buds;[3][12]
• Eucalyptus sideroxylon A.Cunn. ex Woolls subsp. sideroxylon.[13]

Distribution and habitat

Mugga ironbark is widespread and often abundant in woodland from south-eastern Queensland through New South Wales to Victoria. Subspecies improcera is only known from the Barakula State Forest north-northwest of Chinchilla.

Uses

The wood is relatively hard and dense, and is often used for firewood. It has very high resistance to rotting and can be used for fence posts, piers, sleepers. Heartwood dark red, sapwood pale yellow. Very dense, hard, fine grained timber, difficult to work, but polishes to a high sheen. Has been used for furniture, turnery, boat-building, benchtops. Popular as a craft furniture timber during the 1990s and early 2000s, Nicholas Dattner famously used ironbark that had been submerged as a wharf pier for 80 years in a range of tables. At about 1130 kg/m³ it is one of the few timbers that will not float.

The leaves are used in the production of cineole based eucalyptus oil.[14]

Apiarists in New South Wales place hives in red-ironbark woodlands to collect the honey.[7]

Use in horticulture

They are easy to grow from seed and are usually quite true to the parent in form. They are very hardy, needing less than 400mm of rain per year to survive, yet can grow in climates with more than 1000mm/y.

Chemistry

Molecules produced by plants in case of pathogens attacks are called phytoalexins. Such compounds can be implied in the hypersensitive response of plants. High levels of polyphenols (stilbenoids and ellagitannins) in E. sideroxylon wood can explain its natural preservation against rot.[15]

See also

• List of Eucalyptus species

References

1. "Eucalyptus sideroxylon". Australian Plant Census. Retrieved 23 December 2019.
2. Hill, Ken. "Eucalyptus sideroxylon". Royal Botanic Garden Sydney. Retrieved 22 December 2019.
3. Brooker, M. Ian H.; Slee, Andrew V. "Eucalyptus sideroxylon". Royal Botanic Gardens, Victoria. Retrieved 23 December 2019.
4. "Eucalyptus sideroxylon". Euclid: Centre for Australian National Biodiversity Research. Retrieved 29 May 2020.
5. Chippendale, George M. "Eucalyptus sideroxylon". Australian Biological Resources Study, Department of the Environment and Energy, Canberra. Retrieved 23 December 2019.
6. Messina, Andre; Stajsic, Val. "Eucalyptus sideroxylon subsp. sideroxylon". Royal Botanic Gardens, Victoria. Retrieved 23 December 2019.
7. Dean Nicolle (30 April 2010). "An illustrated guide to Australia's gum blossoms". Australian Geographic. Retrieved 19 November 2017.
8. "Eucalyptus sideroxylon". APNI. Retrieved 23 December 2019.
9. Woolls, William (1887). "Notes on Eucalyptus leucoxylon (Series 2)". Proceedings of the Linnean Society of New South Wales. 1: 859–860. Retrieved 23 December 2019.
10. Backer, C.A. (1936). Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch-Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten (Edition Nicoline van der Sijs).
11. "Eucalyptus sideroxylon subsp. improcera". Australian Plant Census. Retrieved 23 December 2019.
12. Bean, Anthony R. (2010). "A new subspecies of Eucalyptus sideroxylon A.Cunn. ex Woolls (Myrtaceae) from Queensland". Austrobaileya. 8 (2): 139–141. JSTOR 41739124.
13. "Eucalyptus sideroxylon subsp. sideroxylon". Australian Plant Census. Retrieved 23 December 2019.
14. Boland, D.J., Brophy, J.J., and A.P.N. House, Eucalyptus Leaf Oils, 1991, ISBN 0-909605-69-6
15. Hart, John H.; Hillis, W. E. (1974). "Inhibition of wood-rotting fungi by stilbenes and other polyphenols in Eucalyptus sideroxylon". Phytopathology. 64 (7): 939–48. doi:10.1094/Phyto-64-939.

Department of Primary Industries: Red Ironbark