Eucalyptus cladocalyx

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Sugar gum
Eucalyptus cladocalyx (1).jpg
Eucalyptus cladocalyx habit
Scientific classification edit
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Myrtales
Family: Myrtaceae
Genus: Eucalyptus
E. cladocalyx
Binomial name
Eucalyptus cladocalyx
E. cladocalyx.JPG
E. cladocalyx, field distribution

Eucalyptus corynocalyx F. Muell. Eucalyptus langii Maiden & Blakely

Eucalyptus cladocalyx leaves and bark
Kino oozing from a small fissure on a Eucalyptus cladocalyx
Eucalyptus cladocalyx fruit
Two Sugar Gums growing next to the Wollundry Lagoon

Eucalyptus cladocalyx, commonly known as sugar gum, is a species of eucalypt tree found in the Australian state of South Australia. It is found naturally in three distinct populations - in the Flinders Ranges, Eyre Peninsula and on Kangaroo Island. It has no known close relatives.[1]


The tree notable for its mottled colourful yellow to orange bark, strongly discolourous leaves and inflorescences grouped on leafless branchlets inside the tree crown. The old bark is smooth and grey, shedding in irregular patches to expose the fresh yellowy-brown bark. Flowers are creamy-white in summer. The capsules are barrel to urn shaped.

Sugar Gums from the Flinders Ranges reach up to 35 metres (115 ft) in height[1] and have the classic "gum" habit - with a straight trunk having a dbh of 1 to 1.5 m (3 ft 3 in to 4 ft 11 in) and steep branches occurring about halfway up. Each main branch ends with its own little canopy. These are commonly cultivated as farm windbreaks and for timber. However, Eyre Peninsula and Kangaroo Island trees are much shorter typically between 8 to 15 m (26 to 49 ft) in height and often have crooked trunks and a dbh of 0.4 m (1 ft 4 in).[1] The crown has an open spreading habit with a typical spread of 12 to 15 m (39 to 49 ft).[2]

The strongly discolorous, glossy adult leaves are arranged alternately supported on a petiole that is 0.9 to 2.7 cm (0.35 to 1.06 in) in length. The leaf blade is darker green on upper side and paler below with slightly falcate to lanceolate shape and a length of 8 to 17 cm (3.1 to 6.7 in) and a width of 1.2 to 3.2 cm (0.47 to 1.26 in) with a base usually tapering to the petiole. The side-veins in the leaf are at an acute or wider angle and densely reticulate. The intramarginal vein is parallel to but removed from margin with small and obscure oil glands.[3]

It flowers in summer producing white-cream-yellow flowers.[2] The axillary unbranched inflorescence occur in groups of buds 7, 9 or 11 buds per umbel. The oblong pale green, yellow to creamy mature buds have a length of 0.8 to 1.1 cm (0.31 to 0.43 in) and a width of 0.4 to 0.5 cm (0.16 to 0.20 in). The buds are often longitudinally striated and scarred with a rounded operculum, inflexed stamens and cuboid to oblong anthers. The urceolate or barrel-shaped longitudinally ribbed fruits that form after flowering are 0.7 to 1.5 cm (0.28 to 0.59 in) in length and 0.5 to 1 cm (0.20 to 0.39 in) wide with a descending disc and three or four enclosed valves. The light grey to brown seeds within the fruit have a flattened-ovoid shape that can be pointed at one end and are 1.5 to 3 mm (0.059 to 0.118 in) long.[3]


The species was first formally described by the botanist Ferdinand von Mueller in 1853 as part of the work Diagnoses et descriptiones plantarum novarum, quas in Nova Hollandia. as published in the journal Linnaea: ein Journal für die Botanik in ihrem ganzen Umfange, oder Beiträge zur Pflanzenkunde.[4] There are two known synonyms for the species; Eucalyptus corynocalyx as described by Ferdinand von Mueller and Eucalyptus langii as described by Joseph Maiden & William Blakely.[5]

The specific epithet is taken from the Greek words clados meaning branch and calyx meaning calyx in reference to the leafless branchlets that bear the flowers.[3]


E. cladocalyx is endemic to three distinct populations in the southern parts of South Australia. It is found in southern and central-eastern parts of the Eyre Peninsula, through much of the Flinders Ranges and on Kangaroo Island. It is most likely part of relic forests of wetter climates from the pst.[3]

It has now become naturalised in the South West region of Western Australia, in southern Victoria, and beyond its native range in some parts of south-eastern South Australia. Also naturalised overseas in northern and southern Africa, in California, Hawaii,[5] Arizona, Israel, Chile, Greece, Portugal]] and Spain.[6]


The tree is commonly planted across southern Australia for use as a windbreak or shelterbelt, or for timber and firewood production. The wood is termite resistant, with moderate strength and durability and can be used for furniture, flooring, posts, construction timber and for railway sleepers.[1]

It is a fast growing tree but is best planted in open sun in clay, loam or sandy soils.[2] It is an efficient user of water[6] and drought and frost tolerant with flowers that attract bees. It is also known to be a suitable breeding habitat for the Yellow-tailed Black-Cockatoo.[2]

E. cladocalyx is well adapted to regular bushfires that can resprout epicormically and produce a massive amount of seedlings through wind dispersal of seeds.[6]

The hard and heavy heartwood is a pale yellow-brown colour and has fine uniform texture with an interlocked grain. The density of the air dried wood is around 1,105 kg/m3 (1,863 lb/cu yd) and is moderately durable.[7]


  1. ^ a b c d "Eucalyptus cladocalyx". Florabank. Retrieved 30 July 2017.
  2. ^ a b c d "Eucalyptus cladocalyx". Factsheet. Botanic Gardens of South Australia. Retrieved 25 November 2018.
  3. ^ a b c d "Eucalyptus cladocalyx". Euclid. CSIRO. Retrieved 25 November 2018.
  4. ^ "Eucalyptus cladocalyx F.Muell". Atlas of Living Australia. Global Biodiversity Information Facility. Retrieved 30 July 2017.
  5. ^ a b "Eucalyptus cladocalyx F. Muell". Weeds of Australia. Queensland Government. Retrieved 30 July 2017.
  6. ^ a b c "Eucalyptus cladocalyx (sugar gum)". Invasive Species Compendium. Centre for Agriculture and Bioscience International. Retrieved 25 November 2018.
  7. ^ "Sugar gum Eucalyptus cladocalyx". Forest Products Commission Western Australia. Retrieved 25 November 2018.