Metrosideros bartlettii J.W.Dawson

Bartlett’s rātā, rātā moehau

New Zealand endemic.

Easily grown from fresh seed, if seed can be obtained. Although the plant is in cultivation, most of the cultivated plants come from one tree.

North Island, Northland, Te Paki, where it is only known from three forest remnants near Spirits Bay and Waitiki. Cultivated in a few parks and gardens in the North Island and known from Christchurch and Dunedin in the South Island of New Zealand.

• Forest tree (up to 30 m tall).
• Bark pale grey to whitish, shedding in tissue-paper-like flakes.
• Juvenile leaves pale yellow-green, adult leaves dark glossy green above, paler below.
• Leaf tips abruptly sharply pointed.
• Leaf margins hairy when young.
• Flowers white.
• Calyx tube as wide as the fruit.

Emergent tree up to 30 m tall, often starting off as epiphyte on trees or tree ferns.

Bark pale grey to whitish, shedding in tissue-like flakes. Young branchlets often dark red, 4-angled to rounded, finely hairy, becoming hairless with age. Trunk up to 1 m or more in diam.

Leaves arranged in opposite pairs, each pair being at right angles to the pair below, leathery, elliptic to ovate, 30–45(–50) mm long, 15–25 mm wide, juvenile leaves pale yellow-green, glossy, adult leaves dark glossy green above, paler below, leaf surface flat, not puckered, midrib raised, oil glands slightly visible on lower surfaces; margins entire, sparsely hairy when young, tips abruptly sharply pointed (attenuate); leaf stalks ± 5 mm long, hairy.

Flowers in rounded terminal clusters, cluster-branchlets often 3-flowered, or flowers solitary on cluster axis. Flowers ± 3–4 mm in diam., mature flower stalks ± 3 mm long, petals 5, elliptic to ovate, white, 2.5–3 mm × 1.8–2 mm; sepals 5, tips free, persistent, stalks and base of flowers and outer surface of sepals hairy; stamens white, filaments 5–9 mm long, much longer than petals. Main flowering period: spring.

Fruit dry, ± 2.5–3 mm wide, persistent sepals, upper part of capsule raised above the persistent calyx tube, calyx tube as wide as fruit, seeds released through open valves.

The habit of M. bartlettii is similar to M. robusta, but the former is diagnosed by pointed leaf tips (instead of a notched tip), the sparsely hairy leaf margin on young foliage, white flowers (instead of mainly red or rarely yellow) and pale grey to whitish tissue-paper-like bark.

Metrosideros bartlettii, with only 12 known trees left in the wild, with an ongoing risk from possum (Trichosurus vulpecula) browse and ineffectual seed production (as there are only five remaining effective genotypes known, all isolated from each other), is at extreme risk of extinction. A further complication is that the species is also susceptible to myrtle rust (caused by Austropuccinia psidii) which has been found infecting cultivated plants. For all these reasons this species has been assessed as Threatened – Nationally Critical.

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.

• CitSciHub
• Flora of New Zealand Online
• GBIF
• iNaturalist NZ
• NZPCN