Species

Kunzea amathicola

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: sand-dwelling

Common Name(s)

Rawiritoa, kanuka

Current Conservation Status

2018 - Threatened - Nationally Vulnerable

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2013 - At Risk - Declining

Authority

Kunzea amathicola de Lange et Toelken

Family

Myrtaceae

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 12.4–4.8 × 3.6–6.0 mm.

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

None first described in 2014

Distribution

Endemic. New Zealand: North and South Islands - most westerly from Te Paki south to Wellington, and from Farewell Spit south and west to West Whanganui Inlet. Also recorded from Kawau and Hauturu (Little Barrier Islands) and once from the northern Hauraki Plains

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)

Features

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.

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 Three Kings Island s 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 amathicoal 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”) is appropriately listed under 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.

Chromosome No.

2n = 22

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

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, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington.

de Lange, P.J. 2014: A revision of the New Zealand Kunzea ericoides (Myrtaceae) complex. Phytokeys 40: 185p doi: 10.3897/phytokeys.40.7973.

 

This page last updated on 1 Sep 2014