Eucalyptus shiressii Maiden & Blakely
Eucalyptus punctata, commonly known as grey gum, is a large tree of the myrtle family, Myrtaceae, native to South East Queensland and eastern New South Wales, where it specialises in poor soils such as Sydney sandstone. Its leaves are one of the favoured foods of the koala. The tree's common name comes from its bark, which takes a greyish cast at about one year of age (see photograph). On most trees this bark is partly shed, revealing a bare and slightly orange or brown tinted smooth surface. The white flowers appear over the summer.
Swiss naturalist Augustin Pyramus de Candolle first described the grey gum in 1828. Common names include grey gum and grey irongum. The species name is the Latin adjective punctata "spotted" and refers to the oil glands which give the leaves a dotted appearance.
It is one a group of related species known collectively as large-fruited grey gums found in eastern Australia, the others being E. longirostrata from eastern Queensland, E. biturbinata from the New England region, and E. canaliculata from the vicinity of Gloucester and Dungog in central-northern New South Wales.
The grey gum grows as a large tree to 35 m (100 ft) high, with bark of various shades of grey, white and orange hues, which sheds in large sheets, giving the trunk a patchy appearance. The glossy dark green adult leaves are falcate (sickle-shaped) or lanceolate and measure 8–15 cm (3.4–6 in) in length by 1.5–3 cm (0.6–1.2 in) wide. The flowers are white, and are in bloom from December to March.
Distribution and habitat
It grows in tall open sclerophyll forest, associated with such species as red bloodwood (Corymbia gummifera), pink bloodwood (C. intermedia), spotted gum (C. maculata), white stringybark (E. globoidea), sydney peppermint (E. piperita), blackbutt (E. pilularis), yellow box (E. melliodora), mountain grey gum (E. cypellocarpa), narrow-leaved ironbark (E. crebra), grey ironbark (E. paniculata), broad-leaved white mahogany (E. umbra), white mahogany (E. acmenoides), and apples (Angophora species).
The grey gum regenerates by regrowing from the base and branches after bushfire. Trees live for over a hundred years. The grey-headed flying fox (Pteropus poliocephalus) eats the flowers, while the leaves form a staple of the diet of the koala (Phascolarctos cinereus). Leaves in winter contain less nitrogen than those in summer, which the koalas make up for by eating more in winter months. The brown-headed honeyeater (Melithreptus brevirostris) and yellow-tufted honeyeater (Lichenostomus melanops) have been observed eating gum exudate from the stems.
The timber is very hard and durable, and used in construction and for railway sleepers. The multicoloured bark of Eucalyptus punctata that appears from time to time gives the tree some horticultural appeal, and it has potential applications in large parks, reserves and fields.
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- "Eucalyptus punctata". EucaLink: A Web Guide to the Eucalyptus. Royal Botanic Gardens, Sydney. Retrieved 2 September 2011.
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- Cork, S. J. (1986). "Foliage of Eucalyptus punctata and the Maintenance Nitrogen Requirements of Koalas, Phascolarctos cinereus". Australian Journal of Zoology 34 (1): 17–23. doi:10.1071/ZO9860017.
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