NZ Myrtaceae Key - Online edition

Metrosideros perforata (J.R.Forst. & G.Forst.) A.Rich.


Common Names

akatea, akatorotoro, small white rātā

Origin

New Zealand endemic.

Cultivation

Plants raised from seed tend to form a climber if there is support; cutting grown material tends to form compact shrubs. Metrosideros perforata ‘Wee Willie Winkie’ is a cultivar selected for its variegated leaves.

Distribution

Occurs from Three Kings and the North Island (where it is absent from the Central Volcanic Plateau) to the South Island (to northern Otago and northern Fiordland). In the North Island it is present in coastal to montane situations but in the South Island it has a mainly coastal distribution.

Distinguishing Features

Habit

Long-climbing vine up to ± 20 m when supported, or where support is absent forming a shrub or dense intertangled shrubland; sparsely branched when young, heavily branched with age.

Bark and Stem/Trunk

Bark furrowed, dark grey to brown-black, separating into thick, squarish flakes. Branchlets round, with short brown hairs.

Leaves

Leaves opposite, ranked on either side of stem and lie in one plane, although adult leaves tend to spread around the stem, leathery, 6–12 mm long, 5–9 mm wide, broad-ovate to broad-oblong, juvenile leaves sometimes circular, upper surface dark green, lower surface paler, leaf surface flat, not puckered, upper surface hairless, lower surface hairy, oil glands visible on both surfaces, especially below; margins entire and recurved (revolute), tips rounded; leaf stalks present (1–3 mm long).

Flowers

Flowers in small, few-flowered clusters crowded towards tips of branchlets, flowers ± 6–7 mm in diam., flower stalks ± 5–10 mm long, petals 5, rounded, ± 1.5–3.0 × 1.5–3.0 mm, white, falling early; sepals 5, broadly triangular, tips free, persistent, hairless, stamens white, filaments 8–10 mm long. Main flowering period: late spring to early autumn.

Fruit

Fruit dry, rounded, ± 4–5 mm wide, valves raised as a dome above the calyx tube, calyx tube as wide as fruit.

Similar Species

Distinguishable from the other white-flowered Metrosideros vine species by distinctly gland-dotted leaves (most obvious on the leaf underside), and by the adult leaves <12 mm long, small white flowers with stamens whose filaments are ± 10 mm long accompanied by capsule valves raised as a dome above the flower base (receptacle) rim before opening.

Notes

Metrosideros perforata was given a status of Threatened – Nationally Vulnerable in 2018. Since then myrtle rust (caused by Austropuccinia psidii) has been noted on M. perforata.

Metrosideros is a genus of more than 50 species of trees, shrubs and vines, mostly found in the Pacific region. New Zealand is well represented by having 12 endemic species.

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