Kunzea amathicola
Common name
rawiritoa, kānuka
Synonyms
None first described in 2014
Family
Myrtaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Trees & Shrubs - Dicotyledons
Chromosome number
2n = 22
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – an interim threat classification status has not been assessed by the NZTCS panel.
- Conservation status of New Zealand indigenous vascular plants, 2017 . 2018. Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Vulnerable | Qualifiers: DP, De
Previous conservation status
2013 | At Risk – Declining
Brief description
Shrubs or trees of the coastal sites (especially active dune field) of the western North and north-western South Island. Foliage dimorphic with ‘juveniles’ forming small flowering shrubs on active dunes and ‘adults’ dense forest on more stable dunes. Branches numerous bearing masses of dark green glossy leaves and sprays of usually widely spaced white flowers. Branchlets and leaf margins densely covered in long silky hairs (hairs on leaf margins in thick wefts meeting at leaf apex). Leaves to 25 mm long, soft to grasp. Flowers large (up to 12.5 mm diameter) borne in elongated sprays (the flowers seemingly solitary (monadic)), white with a red centre, each flower subtended by a broad leaf-like bract. Fruit a dry capsule 2.4–4.8 × 3.6–6.0 mm.
Distribution
Endemic. New Zealand: North Island (mostly westerly from Te Paki south to Wellington; also recorded from Kawau Island and Te Hauturu-o-Toi / Little Barrier Island, and once from the northern Hauraki Plains), South Island (from Farewell Spit south and west to West Whanganui Inlet).
Habitat
Coastal to lowland. A species mostly inhabiting mobile sand, sand dunes and sandy soils. Occasionally extending inland onto clay soils (at Unuwhao (Te Paki), Around the Kaipara Harbour, Wellington and around Puponga)
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Detailed description
Shrubs or trees up to 15 m tall; heterophyllous. Those with persistent juvenile foliage mostly present in exposed conditions and unstable habitats, or at the margins of adult stands, usually forming domed, spreading shrubs up to 2 × 3 m with numerous erect to ascending, often interwoven branches; those with adult foliage forming single to multi-trunked trees up to 18 × 8 m, with very broad, spreading canopies. Trunk 1–2, 0.10–0.85 m d.b.h. Bark grey or grey-brown, ± elongate, tessellated, firmly attached, detaching basally with age, and peeling upwards along trunk in broad, tabular strips. Branches numerous, erect to suberect not spreading, often interwoven, arching and spreading; branchlets numerous, slender, branchlet indumentum copious, persistent; hairs silky, antrorse-appressed, usually flexuose, 0.23–0.50 mm long. Leaves sessile to shortly petiolate, well-spaced to crowded along branchlets, dark glossy green above, paler beneath. Juvenile lamina 2.4–5.3 × 1.2–2.3 mm, ovate, broadly ovate, rhomboid to obovate, adult lamina 6.0–12.5 × 1.8–3.8 mm, oblong, oblong-obovate, broadly oblanceolate to broadly lanceolate; apex of both juvenile and adult lamina obtuse, rounded to subacute, rostrate, base attenuate to narrowly attenuate; lamina margin completely obscured by a dense covering of antrorse-appressed hairs aligned in a thick, up to 0.6 mm wide, white, plumose band meeting with abaxial midrib hairs at the leaf apex. Inflorescence usually a well-spaced, elongate, 5–20-flowered botryum up to 200 mm long. Inflorescence axis densely invested with silky, antrorse-appressed, weakly flexuose hairs. Pherophylls persistent, foliose, spreading, dark glossy green, oblong, oblong-obovate, broadly obovate to elliptic; strongly recurved, to about half of total length or flat; juvenile lamina 2.0–5.3 × 1.2–2.3 mm, adult lamina 4.1–6.0 × 1.6–3.1 mm; apex obtuse, cuspidate, base attenuate; lamina margin obscured by dense covering of antrorse-appressed hairs. Pedicels 1.3–4.9 mm long, sparsely to densely invested in antrorse-appressed, weakly flexuose, silky hairs. Flower buds pyriform to hemispherical, apex usually flat or weakly domed prior to bud burst; calyx valves not meeting. Flowers 6.8–12.5 mm diameter. Hypanthium 1.9–4.0 × 3.0–5.6 mm, dark green or red-green; broadly obconic, turbinate to hemispherical, usually densely covered in silky, antrorse-appressed hairs, sometimes glabrous. Calyx lobes 5–8, 0.6–1.4 × 0.6–1.8 mm, ovate, ovate-truncate to broadly obtuse, pale green to red-green; margins glabrescent. Receptacle green at anthesis, darkening to crimson after fertilisation. Petals 5–8, 1.8–3.7 × 2.0–4.0 mm, white, orbicular to broadly ovate, apex rounded, margins ± finely and irregularly denticulate or crimped, oil glands colourless. Stamens 38–90, filaments white. Anthers dorsifixed, 0.40–0.60 × 0.20–0.35 mm, ellipsoid, ovoid-ellipsoid or broadly scutiform, latrorse. Pollen white. Anther connective gland either absent or if present prominent, deep golden-yellow to orange when fresh, drying orange to pink, spheroidal, rather finely papillate. Ovary 5–6 locular, each with 23–42 ovules in two rows on each placental lobe. Style 2.0–3.2 mm long at anthesis, white or pinkish-white; stigma broadly capitate, at least 1.5× width of style, flat, greenish-white or pale pink, flushing red after anthesis, surface finely granular-papillate. Fruits 2.4–4.8 × 3.6–6.0 mm, dark green to chesnut-brown maturing grey, broadly obconic, turbinate or hemispherical, rarely broadly cupular; finely hairy to glabrescent. Seeds 1.2–1.7 × 0.3–0.6 mm, oblong, oblong-obovate, narrowly ellipsoid to cylindrical; testa semi-glossy, orange-brown to dark brown; surface coarsely reticulate.
Manaaki Whenua Online Interactive Key
Similar taxa
Kunzea amathicola is distinguished for the other New Zealand Kunzea species by its heterophyllous habit (with different juvenile and adult foliage types and the tendency for apparent juveniles to flower and fruit), by the obovate leaves with distinctly hairy leaf margins and midribs (with the hairs meeting at the leaf apex rather than just short of it), and distinctive elongate inflorescences. It is most similar to Kunzea linearis and K. triregensis. Kunzea amathicola is distinguished from K. linearis by its non linear leaves, heterophyllous growth habit, elongate inflorescences bearing widely spaced, pedicellate flowers. Kunzea triregensis is endemic to the Manawatāwhi / Three Kings Islands where it appears to be the only Kunzea species present. It differs from K. amathicola by having lanceolate to elliptic pherophylls, and inflorescences that may branch toward the base or near the apices into smaller elongate lateral or more rarely 3-flowered subcorymbiform botrya. For further distinctions see de Lange (2014).
Flowering
July–June
Flower colours
White
Fruiting
August–June
Propagation technique
Easily grown from fresh seed. Can also be struck with difficulty from semi-hardwood and hardwood cuttings. Kunzea amathicola is a very fast growing and attractive species best suited to being planted in a sunny, well drained situation.
Threats
Kunzea amathicola as K. aff. ericoides (a) (AK 286081; “sand”) was listed as ‘At Risk / Declining’ by de Lange et al. (2013). Although widespread this species mostly now occupies highly fragmented and/or relict habitats, in many it is still being cleared for firewood. Very few stands of this species are reserved – the best of these are probably those at Farewell Spit and the adjacent Puponga area.
When myrtle rust (Austropuccinia psidii) was detected in New Zealand (May 2017) the conservation status was upgraded as a precautionary measure to ‘Threatened – Nationally Vulnerable’ because, on best advice, it was believed that no indigenous Myrtaceae had resistance to the myrtle rust disease (de Lange et al. 2018). Currently there have been no reports of infected wild trees of Kunzea but inoculation trials of the New Zealand species has demonstrated they are susceptible, and further that over time, infected specimens will die. Only time will tell if wild populations of Kunzea will be threatened by this rust fungus.
Myrtle rust (Austropuccinia psidii) is an invasive fungus that threatens native myrtle species. Learn more myrtlerust.org.nz.
Etymology
kunzea: Named after Gustav Kunze (4 October 1793, Leipzig -30 April 1851), 19th century German botanist from Leipzig who was a German professor of zoology, an entomologist with an interest mainly in ferns and orchids
amathicola: From the Greek ammos ‘sand’ and the suffix -cola ‘dweller, inhabitant’, refers to the plant’s tendency to be found in sandy areas
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 1 September 2014. Description modified from de Lange (2014).
References and further reading
de Lange PJ. 2014. A revision of the New Zealand Kunzea ericoides (Myrtaceae) complex. Phytokeys 40: 185 p. https://doi.org/10.3897/phytokeys.40.7973.
de Lange PJ, Rolfe JR, Barkla JW, Courtney SP, Champion PD, Perrie LR, Beadel SM, Ford KA, Breitwieser I, Schönberger I, Hindmarsh-Walls R, Heenan PB, Ladley K. 2018. Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series 22. Department of Conservation, Wellington, NZ. 82 p. https://www.doc.govt.nz/globalassets/documents/science-and-technical/nztcs22entire.pdf.
de Lange PJ, Rolfe JR, Champion PD, Courtney SP, Heenan PB, Barkla JW, Cameron EK, Norton DA, Hitchmough RA. 2013. Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington, NZ. 70 p. https://www.doc.govt.nz/globalassets/documents/science-and-technical/nztcs3entire.pdf.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Kunzea amathicola Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/kunzea-amathicola/ (Date website was queried)