Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson

Eucalyptus citriodora Hook.

lemon-scented gum, spotted gum

Australia: a tall forest tree from temperate and tropical eastern Australia, from northern New South Wales to northern Queensland.

In New Zealand exclusively found in cultivation; occasional in parks and large gardens.

Scattered records from mainly urban areas in the North Island and northern South Island of New Zealand.

• Tall tree with pale, smooth bark over the whole trunk.
• All leaves lemon-scented when crushed. Mature leaves alternate, stalked, blade narrowly lanceolate to sickle-shaped, to 230 mm long, with narrow tapered tip, and numerous large oil glands.
• Flowers in clusters of three, grouped in small branched flowerheads in axils of leaves towards ends of branches, white. Bud cap rounded to conical or slightly narrowly pointed.
• Fruit a stalked, urn-shaped or barrel-shaped woody capsule, to 15 mm long and 12 mm wide, with disc descending below the rim, 3 enclosed valves.

Tree to 50 m tall.

Bark smooth throughout, white to pink or coppery, often powdery, shedding in thin curling flakes. Mottling of trunk often not pronounced, but there may be patches of blue-grey older attached bark; ribbons absent. Hairs and adventitious roots absent. Young stems rounded in cross-section, bristly hairy to rough-surfaced.

Mature leaves alternate, blade narrowly lanceolate to sickle-shaped, (70–)100–230 mm long, 6–28(–35) mm wide, glossy, green, same colour above and below, strongly feather-veined, vein reticulation very dense, intramarginal vein parallel to and just within leaf margin, numerous large oil glands; margins smooth; tips narrowly pointed; leaf bases tapering to leaf stalks; leaf stalks 10–25 mm long. Leaves lemon-scented when crushed.

Juvenile leaves always stalked, opposite for 2 or 3 pairs then alternate, ovate to lanceolate, 80–210 mm long, 32–80 mm wide; the base usually attached to the underside of the blade for many leaf nodes (peltate), green; stalk and blade bristly hairy to rough-surfaced for many nodes.

Flowers in clusters of three, grouped in small branched flowerheads in axils of leaves towards ends of branches, each cluster stalk round, 3–7 mm long. Mature buds are free, club-shaped, 6–10 mm long, 5–7 mm wide, green to creamy, usually smooth. Bud cap rounded to conical or slightly narrowly pointed, flowers (stamens) white; in mature open flowers, petals and sepals absent. Main flowering period: autumn to winter, but some flowers may occur in spring or summer.

Capsules woody, stalked (1–7 mm long), urn-shaped or barrel-shaped, 8–15 mm long, 7–12 mm wide, disc descending below the rim, valves 3, enclosed.

The tall, smooth, pale trunk and lemon-scented leaves are distinctive.

Corymbia is a genus of more than 100 species, mainly in Australia but also extending into New Guinea. Until 1990, Corymbia was included in the genus Eucalyptus and there remains debate among botanists as to whether separating them is valid. Corymbia is currently an accepted name in the Australian Plant Census (APC).

• Australia’s Flora: Growing Native Plants
• EUCLID
• GBIF
• iNaturalist NZ
• PlantNET: New South Wales Flora Online
• Plants of South Eastern New South Wales
• VicFlora: Flora of Victoria
• Weeds of Australia: Biosecurity Queensland