Australian native trees: how to identify the main groups

Eucalypts: bark first, then buds and gumnuts

"Eucalypt" covers three related genera of the myrtle family. The Australian Native Plants Society (ANPSA) counts over 900 species: about 800 Eucalyptus, about 115 Corymbia (the bloodwoods and spotted gums) and 13 Angophora. PlantNET says Eucalyptus alone has over 800 species, all but 16 endemic to Australia, with about 240 in New South Wales.

Bark sorts them into everyday groups. Botanists split eucalypts into "rough barks", whose bark stays on the trunk, and "smooth barks", which shed it in patches or ribbons. ANPSA defines the common names:

• Gums: smooth bark, shed regularly; the name comes from the sticky kino some species ooze.
• Stringybarks: bark that pulls away in long fibres.
• Ironbarks: hard, deeply furrowed bark that stays on.
• Boxes: persistent bark with short fibres.
• Bloodwoods: timber with pockets of dark red kino.
• Peppermints: crushed leaves smell of peppermint.

Then check the buds. In Eucalyptus and Corymbia each bud is covered by an operculum, a cap that drops off as the flower opens. Angophora has no cap, and its adult leaves are opposite, where Eucalyptus leaves usually look alternate. Fruit shape and size, and whether the valves stick out of the gumnut, separate species within a group.

Expect two leaf forms. Young eucalypts grow juvenile leaves, often opposite and a different colour, before switching to the adult leaves of the crown. The Hunter Region Landcare Network's guide to identifying a gum tree works through a real example: bark first, then leaves, then the number of buds in each cluster, then the gumnut's disc and valves. Even then, it concludes with two candidates. Our eucalyptus page covers the species planted most often overseas.

Wattles: phyllodes and fluffy flowers

PlantNET puts Acacia at about 960 species in Australia, more than 235 of them in New South Wales. Seedlings grow feathery bipinnate leaves. On mature plants those are usually replaced by phyllodes, flattened leaf stalks that look like simple leaves.

The flowers are tiny and packed into round, oval or cylindrical heads, so a wattle in bloom looks covered in yellow or cream pom-poms or bottle-shaped rods. The fruit is a pod, leathery or woody, that usually splits open.

The Australian National Botanic Gardens describes the national floral emblem, the golden wattle (Acacia pycnantha), as having bright green, leathery phyllodes 6 to 20 cm long and large, fragrant flower heads of up to 80 small flowers in spring. It grows in open forest and woodland understorey in South Australia, Victoria, New South Wales and the ACT, and was proclaimed the emblem in 1988. National Wattle Day is 1 September.

She-oaks: jointed branchlets, not needles

A she-oak looks like a weeping pine until you pull a "needle" apart: it snaps cleanly at a joint. PlantNET describes the family Casuarinaceae as trees and shrubs with slender, wiry, jointed branchlets; the true leaves are reduced to small teeth in whorls of 4 to 20 at each joint, and the segment between two whorls is called an article. Female flowers ripen into a small woody cone that releases winged seeds. Australia has 3 genera and 68 species, in every state.

To split the two main genera, look at a ripe cone and its seeds. Casuarina has 6 to 20 teeth per whorl, thin cone bracteoles that stick out well beyond the cone, and dull grey or yellow-brown seeds. Allocasuarina has 4 to 14 teeth per whorl, thick bracteoles that barely stick out, and shining red-brown to black seeds.

Banksias, paperbarks and bottlebrushes

Banksias carry dense, many-flowered spikes on a woody central stalk. After flowering, the stalk becomes a woody "cone" studded with follicles that split into two hard valves to release the seed. PlantNET counts about 76 species in Australia, nearly all endemic, in every state. The leaves vary from finely toothed to smooth-edged, which helps separate species.

Paperbarks (Melaleuca) have flowers in spikes or heads with many stamens joined into bundles opposite the petals, which gives the brush look. PlantNET counts about 215 species in Australia, about 210 of them endemic, and uses papery versus hard or corky bark as a split in its key. The red-flowered bottlebrushes grown in gardens have the same brush of stamens.

Native conifers: cypress pines and araucarias

Neither group belongs to the true pines, the genus Pinus, despite the common names.

• Cypress pines (Callitris) carry tiny scale leaves in whorls of three and cones with usually 6 scales in a single ring. PlantNET lists 17 species in Australia, in every state.
• Araucarias, the family of hoop pine and bunya pine, have needle-like or flat leaves arranged in spirals and big woody cones. Australia has 3 genera and 6 species of the family, in Queensland and New South Wales. One of them, the Wollemi pine, grows wild only in Wollemi National Park.

For needle and cone keys that work elsewhere, see our conifer identification guide.

Native trees in the app's Collection

Tree Identifier's Collection, the field-guide catalog that fills in as you identify, includes five Australian trees: blue gum eucalyptus, mountain ash, the paperbark tree, crimson bottlebrush and Norfolk Island pine. Most wattles, she-oaks and banksias are not in it, though a photo of any of them still returns a name. The app needs an internet connection, which matters in the outback.

Across the Tasman the flora is entirely different: see our guide to New Zealand native trees.