mugga, mugga ironbark, red ironbark
NZ Myrtaceae Key - Online edition
Eucalyptus sideroxylon A.Cunn. ex Woolls subsp. sideroxylon
Common Names
Origin
Australia: western New South Wales, extending south into northern Victoria and north to south-eastern Queensland.
Cultivation
In New Zealand occasionally cultivated.
Distribution
A few scattered records from parks and plantations in both the North and South Islands of New Zealand.
Distinguishing Features
- Small to medium-sized tree with dark, thick ironbark throughout, deeply furrowed down the trunk; youngest branchlets grey-white.
- Adult leaves dull green to blue-green, grey-green, grey or waxy grey-white, same colour above and below, alternate, stalked, blade lanceolate, to 140 mm long and 40 mm wide; juvenile leaves always stalked, opposite for 4–7 pairs, then alternate, becoming lanceolate, dull, green to grey-green or waxy grey-white.
- Flowers often pale pink, but may be white, red, pink or pale yellow; in clusters of seven, in leaf axils, stalk of cluster slender, angular in cross-section, erect or hanging downwards. Mature buds free, on long, slender stalks (stalk 3–15 mm long), club-shaped to diamond-shaped, to 15 mm long and 6 mm wide, green to creamy or waxy grey-white, cap conical to narrowly pointed, sometimes warty, staminal ring prominent (stamens joined in a ring at their bases).
- Fruit a stalked woody capsule, cup-shaped to truncated-globose, to 11 mm long and 10 mm wide, staminal ring broad, remaining around the rim of the capsule, then shedding as capsule matures, disc descending inside the capsule rim (sometimes obscured by black staminal ring), valves usually 5, enclosed within the rim.
Habit
Small to medium-sized tree to 25 m tall.
Bark and Stem/Trunk
Ironbark throughout, dark grey, dark brown or black, deeply furrowed down trunk, impregnated with gum deposits; ribbons absent. Adventitious roots and hairs absent. Branchlets may be waxy grey-white. Young stems usually rounded in cross-section, smooth, light grey, may be waxy grey-white.
Leaves
Adult leaves alternate, stalked, blade lanceolate, 50–140 mm long, 10–40 mm wide, base tapering to stalk, dull, green to blue-green, grey-green, grey or waxy grey-white, same colour above and below; side-vein angle to midrib varies, either acute or wider; vein reticulation moderate to dense, intramarginal vein parallel to and just within margin or well removed it, oil glands present; leaf stalk 5–25 mm long.
Juvenile leaves always stalked, opposite for about 4 to 7 pairs then alternate, lanceolate to oblong or narrow with parallel sides, 30–110 mm long, 5–35 mm wide, base tapering to stalk, dull, green to grey-green or waxy grey-white.
Flowers
Flowers in clusters of seven, in leaf axils, stalk of cluster slender, angular in cross-section, erect or hanging downwards, 7–29 mm long. Mature buds are free, on long, slender stalks (stalk 3–15 mm long), club-shaped to diamond-shaped, 6–15 mm long, 4–6 mm wide, green to creamy or waxy grey-white, cap conical to narrowly pointed, sometimes warty, staminal ring prominent (stamens joined in a ring at their bases), flowers (stamens) white, red, pink or pale yellow; in mature open flowers, petals and sepals absent. Main flowering period: autumn, winter and spring.
Fruit
Capsules woody, stalked, stalks 2–15 mm long, cup-shaped to truncated-globose, 5–11 mm long, 5–10 mm wide, staminal ring broad, remaining around the rim of the capsule, then shedding as capsule matures, disc descending inside the capsule rim (sometimes obscured by black staminal ring), valves usually 5, enclosed within the rim.
Similar Species
Eucalyptus sideroxylon and E. leucoxylon have similar leaves, buds, and capsules, although buds and capsules of E. sideroxylon are usually smaller, and foliage of E. sideroxylon is typically more bluish, and may be waxy grey-white. Both have prominent staminal rings on flowers and capsules. An important difference is that E. leucoxylon has flowers in clusters of 3, whereas E. sideroxylon has clusters of 7. The most conspicuous difference is that E. leucoxylon has mostly smooth white or grey-white bark with a little rough, greyish bark at the base, but E. sideroxylon has thick, dark ironbark throughout.
Notes
Two subspecies of E. sideroxylon are accepted in the Australian Plant Census (APC): Eucalyptus sideroxylon subsp. sideroxylon (APC), and E. sideroxylon subsp. improcera (APC), a recently described small, stunted tree that has shorter, wider leaves and longer flower buds than E. sideroxylon subsp. sideroxylon, restricted to inland Queensland, and not known to be present in New Zealand.
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.