Metrosideros umbellata Cav.

rātā, southern rātā

New Zealand endemic.

Easily propagated from fresh seed, but plants grow slowly and take many years to flower unless planted in ideal conditions. Only occasionally planted in parks and gardens of New Zealand. More than 15 cultivars have been selected, including M. umbellata ‘Harlequin’, and other cultivars with variegated leaves, and rare selections with orange, pink, white, and yellow flowers (instead of the usual red); none are common.

Widely distributed in the North and South Islands and Stewart Island of New Zealand as well as the Auckland Islands. In the North Island, locally present from Te Paki south through Northland, the Barrier Islands, Coromandel and Kaimai Ranges with a single occurrence on Mt Pironga in the western Waikato, also Te Urewera and in the southern Tararua Ranges. In the South Island widespread and common from D’Urville Island south, especially in the west, to southern Fiordland, but also present in southern Otago on the east coast.

• Branchlets more or less hairless, mature branches hairless.
• Young shoots and leaves often red-tinged.
• Lower surface of leaves not velvety, oil glands visible on lower surface.
• Leaves lanceolate.
• Leaf tips often extended to a slender point (apiculate).
• Flower clusters of few flowers.
• Stamens ± 20 mm long, and relatively few per flower.

Tree up to 18 m tall with trunk 1 m wide or more, but sometimes reduced to a shrub, particularly in high-altitude localities.

Bark mostly brown to grey-brown, slightly corky or flaky, peeling off in strips. Branchlets round, hairless when mature.

Leaves arranged in opposite pairs, each pair being at right angles to the pair below, leathery, lanceolate, 25–60(–75) mm long, 10–20 mm wide, upper surface of adult leaves dark, glossy green, slightly paler below, juvenile leaves often tinged red, leaf surface flat, not puckered, upper surface and lower surface hairy when young, becoming hairless with age, midrib hardly raised, oil glands visible on lower surfaces; margins entire, slightly revolute; tips acute, often extended to a slender point (apiculate) and twisted; leaf stalks ± 5 mm long.

Flower clusters terminal, few-flowered. Flowers ± 5–8 mm in diam., mature flower stalks ± 1–2 mm long, ± 1 mm wide, petals 5, light red; sepals 5, tips free, persistent; stalks and base of flowers all with silky grey-white hairs, but sepals largely hairless, and becoming hairless with age or flowers almost entirely hairless to begin with; stamens mainly red (rarely orange, pink, white, and yellow), filaments ± 20–25 mm long, much longer than petals. Main flowering period: spring to summer.

Fruit dry, ± 5–8 mm wide, capsule dome occurring below the persistent calyx tube, capsule tube as wide as fruit, capsule splits along sides and below to release seeds.

Superficially similar to M. parkinsonii, but differs in that M. umbellata possesses narrower leaves (lanceolate) and few-flowered clusters borne terminally, as opposed to wider (ovate) leaves and many-flowered clusters borne usually below the leaves.

Often confused with M. robusta with which it often grows (Northland, Barrier Islands, Coromandel Peninsula, Kaimai Range, West Whanganui Inlet) and occasionally hybridises with (Aotea / Great Barrier Island, Tararua Ranges, West Whanganui Inlet, Wakamarama Range). From M. robusta, M. umbellata is easily distinguished by its virtually hairless branchlets, glossy red-tinged new growth and hairless, dark, glossy green leaves with sharply acute, often apiculate tips. Young branchlets of M. robusta are finely covered in reddish hairs with the young growth often coloured dull yellow-red, pinkish red or even apricot, but never glossy, while the adult leaves are dull, dark green (never glossy), and the leaf apices usually notched or uncommonly unnotched, but then the tips are acute but never apiculate (with a slender point) as in M. umbellata.

A variable species. Flower base, stalks and/or flower-cluster stalks described as hairy in the original publication and in the Flora of New Zealand, yet observations of apparently hairless flower clusters exist on iNaturalist NZ. Metrosideros umbellata was given a conservation status of Threatened – Nationally Vulnerable in 2018.

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