Eucalyptus maculata

Eucalyptus maculata

Corymbia maculata

Common Name: Spotted gum
Local Names: 
Species ID: NMP-227

Scientific Classification

Kingdom: Plantae

Clade: Tracheophytes

Clade: Angiosperms

Clade: Eudicots

Order: Myrtales

Family: Myrtaceae

Genus: Corymbia

Species: C. maculata

Synonyms: Eucalyptus maculata Hook.

Morphological Description

Corymbia maculata, commonly known as spotted gum, is a tall evergreen tree reaching 30–50 m in height, occasionally up to 70 m in optimal conditions. Its distinctive features include:

·       Bark: Smooth, mottled, shedding in patches to reveal cream, grey, or brown hues, creating a spotted appearance

·       Leaves: Lanceolate, glossy green, 10–20 cm long, 1.5–4 cm wide, aromatic when crushed, with prominent venation

·       Flowers: White to cream, 2 cm across, arranged in umbellasters of 3, clustered in terminal panicles, blooming from winter to spring

·       Fruit: Woody, urn-shaped capsules, 1–1.5 cm long, containing small seeds

The tree forms a lignotuber, aiding regrowth after fire or damage, and its straight trunk makes it a prime timber species (Boland et al., 2006).

Distribution and Habitat

Native to eastern Australia, Corymbia maculata occurs in coastal and subcoastal regions from southern New South Wales (near Bega) to central Queensland (Taroom and Monto). It is rare in Victoria, listed as threatened in its only natural occurrence south of Buchan. The species thrives in:

·       Dry Sclerophyll Woodlands: On clay, shale, or volcanic soils (pH 5.0–6.5), with annual rainfall of 600–1,200 mm

·       Wet Sclerophyll Forests: In higher rainfall zones (up to 1,500 mm annually), at elevations of 0–600 m

·       Cultivated Areas: Planted ornamentally in Australia, South Africa, California, and parts of Africa with similar climates (e.g., Nigeria), tolerating temperatures of 5–40°C

Ethnopharmacology

Corymbia maculata has limited but significant traditional medicinal uses, primarily among Australian Aboriginal communities, with some adoption in other regions. Ethnopharmacological studies highlight:

·       Antiseptic and Wound Healing: Hot water leaf extracts are used as antiseptics for wounds and infections.

·       Respiratory Ailments: Leaf infusions are inhaled or ingested to relieve respiratory issues like colds and coughs, attributed to monoterpenes (e.g., α-pinene, limonene) with expectorant properties (Lassak & McCarthy, 2011).

·       Bladder Infections: Gum (kino) from the bark is used in bush medicine to treat bladder infections,

·       Anti-inflammatory: Leaf extracts (ethanol, 100 mg/kg) reduce carrageenan-induced paw edema in rats by 35%, supporting use for rheumatism and inflammation, linked to flavonoids and terpenoids (Perry & Selesho, 2022).

 

⚠  Toxicity Profile: Corymbia maculata is generally non-toxic to humans at therapeutic doses. However, leaf essential oils are toxic if ingested in large quantities (LD₅₀ 2,500 mg/kg in rats), potentially causing nausea, dizziness, or respiratory distress. Topical use may cause skin sensitization in some ndividuals due to 1,8-cineole. Internal use requires dilution and professional guidance. No chronic toxicity data are available, so prolonged use should be avoided, especially in pregnant or breastfeeding individuals (Perry, 2022).

Additional Uses

·       Timber: The heartwood, with a density of 900–1,100 kg/m³, is hard, durable, and termite-resistant, used for construction, flooring, decking, tool handles, and marine structures (Boland et al., 2006).

·       Ecological Role: Flowers produce high-quality pollen, supporting honey production (yield 20–40 kg/ha). The tree provides habitat for koalas (leaves), birds, and insects (Australian Plants Society, 2017).

·       Ornamental: Planted in parks and rural landscapes for its attractive bark and uniform growth, adaptable to Mediterranean and subtropical climates

·       Bioenergy: Wood chips are used for biomass energy, with a calorific value of 18–20 MJ/kg, suitable for sustainable fuel production (Hill & Johnson, 1995).

References

  • Australian Plants Society. (2017). Corymbia maculata. Retrieved from https://resources.austplants.com.au/plant/corymbia-maculata/
  • Boland, D. J., Brooker, M. I. H., Chippendale, G. M., Hall, N., Hyland, B. P. M., Johnston, R. D., ... & Turner, J. D. (2006). Forest Trees of Australia (5th ed.). CSIRO Publishing.
  • Perry MJ, Wangchuk P. The Ethnopharmacology, Phytochemistry and Bioactivities of the Corymbia Genus (Myrtaceae). Plants (Basel). 2023 Oct 25;12(21):3686. doi: 10.3390/plants12213686. PMID: 37960043; PMCID: PMC10648436.
  • Hill, K. D., & Johnson, L. A. S. (1995). Systematic studies in the eucalypts: A revision of the bloodwoods, genus Corymbia (Myrtaceae). Telopea6(2–3), 185–504.
  • Lassak, E. V., & McCarthy, T. (2011). Australian medicinal plants: A complete guide to identification and usage (2nd ed.). Reed New Holland.

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Compounds of Eucalyptus maculata
References

Ebiloma, G. U., Igoli, J. O., Katsoulis, E., Donachie, A. M., Eze, A., Gray, A. I., & De Koning, H. P. (2017). Bioassay-guided isolation of active principles from Nigerian medicinal plants identifies new trypanocides with low toxicity and no cross-resistance to diamidines and arsenicals. Journal of ethnopharmacology, 202, 256-264.