Eucalyptus obliqua L’Héritier

brown-top stringybark, messmate, messmate stringybark

Australia: South Australia through southern Victoria, Tasmania and eastern New South Wales, to south-eastern Queensland.

In New Zealand cultivated as a landscape tree of parks and tree collections, and for timber; occasionally naturalised from nearby planted specimens.

Scattered records throughout New Zealand.

• A tree to 90 m tall, or sometimes a multi-stemmed shrub, with bark rough to small branches, or sometimes smooth on smaller, upper branches; rough bark stringy or fibrous, brown to grey-brown, longitudinally furrowed; smooth bark green or grey. Young stems rounded square in cross-section, warty or smooth.
• Adult leaves that are glossy, green, same colour above and below, alternate, stalked, blade lanceolate to sickle-shaped, to 220 mm long and 70 mm wide, usually the two sides of the leaf base meet at different points on the midrib (oblique), side-veins at an acute angle to midrib.
• Juvenile leaves that are glossy, green, initially almost stalkless and opposite for 2–7 nodes, then alternate, stalked, hanging downwards, broadly ovate to lanceolate or sickle-shaped, to 210 mm long and 85 mm wide, base initially lobed to rounded, but by about node 7 the bases meet at different points on the midrib (oblique).
• Flowers in stalked clusters of 11 to 15 or more, in leaf axils, stalk of cluster angular, buds stalked, bud stalks to 8 mm long. Mature buds club-shaped, sometimes broadly, to 9 mm long and 5 mm wide, green to yellow, usually smooth, bud cap conical to rounded, flowers white.
• Fruit are stalked woody capsules, stalk to 5 mm long, cup-shaped or barrel-shaped, to 12 mm long and 11 mm wide, disc usually descending inside the rim, valves 3 or 4, near rim level or enclosed within the capsule.

Tree to 90 m tall, or sometimes a multi-stemmed shrub.

Bark rough to small branches, or sometimes smooth on branches <80 mm diameter; rough bark stringy or fibrous, brown to grey-brown, longitudinally furrowed; smooth bark green or grey; ribbons absent. Hairs and adventitious roots absent. Young stems rounded square in cross-section, warty or smooth.

Adult leaves alternate, stalked, blade lanceolate to sickle-shaped, 60–220 mm long, 15–70 mm wide, usually the two sides of the leaf base meeting at different points on the midrib (oblique), same colour above and below, glossy, green, side-veins at an acute angle to midrib, vein reticulation sparse to moderate, intramarginal vein parallel to and well removed from margin, oil glands usually inconspicuous; leaf stalk 7–34 mm long.

Juvenile leaves glossy, green, initially almost stalkless and opposite for 2–7 nodes, then alternate, stalked, hanging downwards, broadly ovate to lanceolate or sickle-shaped, 60–210 mm long, 23–85 mm wide, base initially lobed to rounded, but by about node 7 the bases are oblique.

Flowers in stalked clusters of 11 to 15 or more, in leaf axils, stalk of cluster angular, 4–25(–31) mm long, buds stalked, bud stalks (1–)3–8 mm long. Mature buds free, club-shaped, sometimes broadly, 4–9 mm long, 3–5 mm wide, green to yellow, usually smooth, bud cap conical to rounded, flowers (stamens) white; in mature open flowers, petals and sepals absent. Main flowering period: summer and autumn, but some flowering may occur from spring through to early winter.

Capsules woody, stalked (stalks 1–5 mm long), cup-shaped or barrel-shaped, 6–12 mm long, 5–11 mm wide, disc usually descending inside the rim, valves 3 or 4, near rim level or enclosed within the capsule.

• Eucalyptus obliqua belongs in the green-leaved ash eucalypt group and is notable for the large, glossy, green, stalked, ovate, juvenile leaves that hang downwards and in which the two sides of the leaf base meet at different points on the midrib (oblique). It is never waxy grey-white. Eucalyptus obliqua is distinguished from the other tall green-leaved ash species of similar wet forests by not having smooth upper trunk or ribbons in the crown of the tree.
• The other common tall green-leaved ash species, E. fastigata and E. regnans, often have paired bud and capsule clusters in leaf axils, whereas E. obliqua has larger, single, cup-shaped or barrel-shaped capsules.
• Eucalyptus obliqua has some characteristics in common with the stringybarks, as well as some other ash eucalypt species and E. pilularis. Stringybark species in this key are E. globoidea, E. eugenioides and E. muelleriana. Other stringybarks in New Zealand include E. agglomerata (blue-leaved stringybark) and E. laevopinea (silvertop stringybark).
• Eucalyptus obliqua has mostly rough bark, but smooth bark on the upper branches. Eucalyptus pilularis has rough bark on the lower trunk, but smooth white bark on the upper trunk and branches. Stringybarks have fibrous rough bark to the small branches (except E. laevopinea, that has smooth white bark on the small limbs).
• Eucalyptus obliqua and E. pilularis have more or less lanceolate adult leaves that are the same colour above and below. Of the stringybarks, E. agglomerata and E. laevopinea also have leaves the same colour above and below. Other stringybarks have leaves distinctly different coloured above and below, or mostly the same colour but colour may be slightly different.
• Eucalyptus obliqua has warty young stems from numerous raised oil glands. Eucalyptus pilularis has young stems 4-sided with flanged edges. Stringybark juvenile stems are rough-surfaced from the presence of star-shaped hairs. Eucalyptus obliqua and E. pilularis juvenile leaves are stalkless whereas stringybark juvenile leaves have short stalks.
• Eucalyptus obliqua is similar to stringybarks in having between 7 and 15 flowers and capsules in a cluster. Eucalyptus globoidea, E. obliqua (and E. agglomerata) have 11–15; E. pilularis and E. eugenioides have 7–15; E. muelleriana (and E. laevopinea) have 7–11. All these stringybarks and E. obliqua have the cluster stalk angular to flattened, some up to 2 cm long; E. pilularis has an angular cluster stalk.
• Eucalyptus obliqua and most stringybarks have rounded to conical bud caps. The bud cap of E. pilularis (and E. agglomerata) is conical and may be narrowly pointed.
• Eucalyptus obliqua, E. muelleriana, E. laevopinea and E. pilularis can have capsules similar in size, but E. obliqua has cup-shaped to barrel-shaped capsules. Eucalyptus pilularis capsules are round to truncated-globular, as are capsules of many stringybarks. Capsules of E. globoidea, E. eugenioides and E. agglomerata are usually smaller and more crowded.

Eucalyptus is a genus of nearly 800 species, most of which are endemic to Australia, with a few species extending to parts of Malesia and as far north as the Philippines.

• EUCLID
• Flora of Australia
• Flora of New Zealand Online
• GBIF
• iNaturalist NZ
• NZPCN
• PlantNET: New South Wales Flora Online
• Plants of South Eastern New South Wales
• VicFlora: Flora of Victoria