blue gum, Sydney blue gum
NZ Myrtaceae Key - Online edition
Eucalyptus saligna Sm.
Common Names
Origin
Australia: south coastal New South Wales to south-eastern Queensland.
Cultivation
In New Zealand predominantly cultivated, for timber or amenity; occasionally naturalised from nearby specimens.
Distribution
Mainly in northern coastal and lowland areas of New Zealand.
Distinguishing Features
- A tall tree with smooth bluish-grey to green-grey or cream bark, with a persistent stocking of rough flaky brown or grey bark for up to four metres above the base.
- Leaves that are glossy, darker green on the upper side, paler beneath, strongly feather-veined, leaf base may be with one side meeting the midrib higher than the other (oblique).
- Flower buds that are stalkless or short-stalked, with conical or narrowly pointed cap, in clusters of 7–11.
- Fruit that are woody capsules, cylindrical, cup-shaped or tapered to the base, in clusters of 7–11, each with disc descending inside rim, valves three or four, and valve tips projecting above the rim of the capsule.
Habit
Tree to 55 m tall.
Bark and Stem/Trunk
Main trunk rough and flaky, grey to grey-brown on basal 1–4 m of trunk; smooth-barked above, bark bluish-grey to cream, green, pink or brown, ribbons absent. Adventitious roots and hairs absent. Young stems rounded in cross-section, warty or smooth.
Leaves
Mature leaves alternate, stalked, lanceolate, feather-veined, tip pointed, base tapering to a leaf stalk evenly or the two sides meeting the midrib at different points (oblique), glossy, dark green above and paler below, hairs absent, 90–190 mm long, 15–40 mm wide. Vein reticulation dense, main side-veins at a relatively wide angle to the midrib, intramarginal veins present, numerous oil glands; leaf stalk 15–30 mm long.
Juvenile leaves opposite for several pairs, then alternate, lanceolate to ovate, or oblong, 37–120 mm long, 15–40 mm wide, margin smooth or slightly scalloped, dark green above and paler below.
Flowers
Flowers in clusters of 7–11, in leaf axils, stalk of cluster flattened, 5–15 mm long. Flower buds stalkless or with short stout stalk; mature buds free, spindle- to diamond- or pear-shaped (5–10 mm long, 3–5 mm wide); bud cap conical or narrowly pointed, smooth, flowers (stamens) white; in mature open flowers, petals and sepals absent. Main flowering period: summer to early autumn.
Fruit
Similar Species
- Eucalyptus botryoides, southern mahogany or bangalay, has similar leaves, buds and capsules, although its buds tend to be larger with conical or hemispherical caps, and the capsules are larger and usually cylindrical to barrel-shaped, with valve tips ± level with capsule rim. The greatest difference is that E. botryoides has thick, rough bark over the whole trunk, to the larger branches.
- Eucalyptus robusta, swamp mahogany or swamp messmate, has similar bark to E. botryoides, that is rough to the small branches. Although its leaves, flower buds and capsules are generally similar, the buds are larger, to 24 × 8 mm, usually with a prominent stalk and long pointed cap, in clusters of 9–15, and the cylindrical woody capsules are also large, to 18 × 11 mm, with valve tips usually joined across the mouth of the capsule.
- Eucalyptus grandis, flooded gum or rose gum, has bark similar to E. saligna, being rough in the basal part of the trunk, then smooth white or greyish bark above. Although its leaves, flower buds and capsules are generally similar, flower bud stalks may be stout, and the capsules are funnel-shaped rather than cylindrical and may be waxy grey-white. The valves (four or five rather than three or four), project above the rim of the capsule, and are broad-based and incurved.
Notes