Metrosideros kermadecensis
Common names
Kermadec pōhutukawa
Biostatus
Native – Endemic taxon
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | At Risk – Naturally Uncommon | Qualifiers: IE, OL
Category
Vascular
Structural class
Trees & Shrubs - Dicotyledons
Simplified description
Tree bearing leathery elliptical leaves that are white underneath and bearing scattered red bristly flowers inhabiting the Kermadec Islands (and planted in New Zealand). Leaves 2–5 cm long, widest at the middle. Flowers composed from many red filaments around a green glossy disk that is fuzzy white underneath.
Flower colours
Red/Pink
Detailed description
Multitrunked (rarely single) tree up to 20 m tall usually with a broadly spreading, domed canopy; trunk up to 3 m diameter, if more than one usually much smaller; trunk surface often covered in adventitious roots. Bark mostly firm, tessellated to platy, grey, grey-brown or whitish, often covered in sparse to dense growths of lichens, liverworts and mosses. Branches erect to spreading, sometimes scrambling across forest floor in which case often rooting freely where touching the ground. Branchlets terete, numerous toward branch ends. Young branchlets, leaf undersides, inflorescence-axes, hypanthia, and sepals densely clad in tomentum, tomentum initially white, maturing dirty grey. Leaves: petioles 5–7 mm long, terete to subterete, very coriaceous; lamina 20–50 × 10–30 mm, dull dark green above with appressed, greyish indumentum along the midrib, sometimes extending along the upper surface of the base of the leaf, orbicular, suborbicular, broadly ovate- to elliptic-oblong, apex obtuse to retuse, base obtuse to cuneately-narrowed, coriaceous, margins weakly to strongly recurved. Inflorescence complex, comprising 2 or more terminal compound corymbiform cymes each bearing numerous flowers; pedicels rigidly stout, 8–12 mm long. Hypanthium obconic to turbinate, sepals coriaceous to subcoriaceous, deltoid to triangular, gland-tipped; petals caducous, fleshy, scarlet, crimson to pink, 2.2–3.2 × 2.0–3.0, orbicular, suborbicular to oblong, glabrescent. Stamens numerous, filaments crimson, 10–23 mm long; anthers versatile, yellow, 1.0 × 0.2–0.4 mm. Nectarial disc initially green at anthesis, maturing red or red-green. Ovary 3-locular, adnate to hypanthium; capsules long-persistent, woody, 3-valved, 6.0–7.2 mm long, receptacle distinctly exserted, outer surface and inner sepals and hypanthial rim covered in appressed white to greyish-white tomentum. Seeds numerous, 2.5–4.5 mm long, yellow to pale orange, very narrowly elliptic to linear, 2–4-angled, body often twisted, laterally compressed, apex curved or hooked.
Similar taxa
Metrosideros kermadecensis is the only species of that genus found on the Kermadec Islands, so in the wild it is not likely to be confused with any other plant. In New Zealand it is commonly cultivated and sometimes sold as pōhutukawa (Metrosideros excelsa). From that species it differs by its smaller leaves (20–50 × 10–30 mm cf. 25–100 × 25–35 mm in M. excelsa), orbicular, suborbicular, broadly ovate- to elliptic-oblong (rather than elliptic to oblong, broadly-lanceolate, acute or obtuse). However, populations of M. excelsa on the Three Kings Islands approach M. kermadecensis in having smaller more consistently elliptic-oblong leaves. In cultivation Metrosideros kermadecensis seems to have no set flowering period with flowers seen throughout the year.
Distribution
Endemic. Kermadec Islands: Raoul, North and South Meyer Islands, Herald Islets (Napier, Nugent and Dayrell)
Habitat
The dominant canopy tree on Raoul Island where it is found from the coastline to the highest peaks. Forms the main tree of both dry and wet forest types. It was supposedly also present on Macauley Island although there are no herbarium specimens known to substantiate this claim.
Threats
Metrosideros kermadecensis is the dominant tree on Raoul Island and it is also prominent on the nearby Meyer Islands and Napier, Dayrell and Nugent in the Herald Islets. Prior to the arrival of myrtle rust (Austropuccinia psidii) in New Zealand, M. kermadecensis was assessed as At Risk – Naturally Uncommon because it is an island endemic which globally occupies a small area. Myrtle rust is an invasive fungus that threatens native myrtle species, so in 2017 the status of M. kermadecensis was reassessed as Threatened – Nationally Critical. Learn more at myrtlerust.org.nz.
Detailed taxonomy
Genus
Family
Synonyms
Metrosideros polymorpha Hook.f. and Metrosideros villosa Kirk are heterotypic synonyms of M. polymorpha Gaudich., Metrosideros villosa Sm.
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
Throughout the year
Fruiting
Throughout the year
Propagation technique
Easy from fresh seed. Cuttings can be grown from water shoots. Hybridises with pōhutukawa (Metrosideros excelsa). Although cold sensitive it can be grown in most places provided there is adequate shelter. This species frequently has some flowers present throughout the year but it rarely has a major flowering event.
Other information
Cultivation
Commonly sold in most garden centres in New Zealand, often—unfortunately—mislabelled as Metrosideros excelsa.
Etymology
metrosideros: Iron heart
kermadecensis: From the Kermadec Islands
Manaaki Whenua Online Interactive Key
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
METKER
Chromosome number
2n = 22
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Critical | Qualifiers: DP, IE, OL
2012 | At Risk – Naturally Uncommon | Qualifiers: IE, OL
2009 | At Risk – Naturally Uncommon | Qualifiers: IE, OL
2004 | Range Restricted
Referencing and citations
References and further reading
Allan HH. 1961. Flora of New Zealand, Volume I. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. Government Printer, Wellington, NZ. 1085 p.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (8 June 2009). Description adapted from Allan (1961) supplemented with data obtained from herbarium specimens, fresh material and observations made on Raoul Island.
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Metrosideros kermadecensis Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/metrosideros-kermadecensis/ (Date website was queried)