Kunzea ericoides (A.Rich.) Joy Thomps.

de Lange, Peter J., 2014, A revision of the New Zealand Kunzea ericoides (Myrtaceae) complex, PhytoKeys 40, pp. 1-185 : 20-27

1. Kunzea ericoides (A.Rich.) Joy Thomps.

Leptospermum ericoides A.Rich in Essai. Fl. N.Z., (1832), 338

Lectotype

(here designated) (Fig. 2). ' Leptospermum ericoides nob. Nlle Zélande’ Herbarium Richard, Ex. Herbier E. Drake, P! Specimen labelled ‘TYPE’ in bold red lettering and bearing two handwritten labels by W. Harris dated 26 July 1989.

Paralectotype

(here designated) (Fig. 3). ' Leptospermum ericoides A.Rich. fl Nlle Zél 338 Nlle Zélande (Astrolabe)' P214999!

Notes.

Allan (1961; p. 322), Thompson (1983) and Harris and Cadic (1998; p. 36) published partial lectotypifications of Leptospermum ericoides A.Rich (see Article 9, of the International Code of Nomenclature ( McNeill et al. 2012). The first two authors did this through their citation of elements of the protologue and by their indication of where type material was lodged, while Harris and Cadic (1998) also published statements of their intent to typify, noting also the location of type material and stating that they had seen ‘Richard’s type’. However, because there are at least two syntypes of Leptospermum ericoides A.Rich. in l’Herbier du Laboratoire de Phanérogamie du Muséum National d’Histoire Naturelle (P) (Figs 2, 3) that bear the distinctive handwriting of Achille Richard (Fig. 2, 3; see also Burdet 1978) and match the protologue with respect to their morphological condition and collection details, and because none of these author’s publications specified which one of these was the lectotype, a further lectotypification is necessary. Of the two sheets that I have seen, both are without date or collector. One (Fig. 2) from the 'Herbarium Richard’ has two labels. The first of these is in Richard’s hand and reads 'Leptospermum ericoides nob. Nlle Zélande’. The second label is printed 'HERB. MUS. PARIS’ and 'HERBIER E. DRAKE’. This sheet has also been stamped by the herbarium staff (P. Morat pers. comm.) ‘TYPE’ and bears two handwritten labels by W. Harris. The upper label states 'Lectotype designation on the basis of ex Herbier E. Drake ex Herbarium Richard (in red) and Leptospermum ericoides Rich.' and the next reads 'Designated Lectotype Leptospermum ericoides A.Rich. Essai. Fl. N.Z. 1832, 338, syn. Kunzea ericoides (A. Richard) Joy Thompson Telopea 2(4) 378, 1983 W. Harris 26 July 1988'. The second herbarium sheet (Fig. 3) also bears two labels (Fig. 2A, B). The first of these (see Fig. 3B) is written in Richard’s hand, and reads ' Leptospermum ericoides A.Rich. fl. Nov. Zél. Nlle Zélande (Astrolabe)', the second (Fig. 3A) is printed 'HERB. MUS. PARIS’. I designate as lectotype, the sheet labelled by Richard ' Leptospermum ericoides nob.' because this matches his protologue (p. 338) with respect to the usage of the possessive Latin abbreviation ‘nob.’ i.e. nobis, meaning 'to us, of us’ in the sense of 'this is my [choice of] name’ ( Stearn 1992; R. O. Gardner pers. comm.). Further, it is the only sheet clearly identified as part of Richard’s herbarium. This was also the sheet designated lectotype by Harris. However, because Harris did not publish this, his lectotypification, although accurate cannot be upheld.

I conservatively designate as paralectotype the second sheet at P. This is because it is without date or collection notes so it is impossible to tell if it was part of the same gathering as the lectotype.

Etymology.

The specific epithet ericoides alludes to the similarity in the growth form of Kunzea ericoides to Erica arborea L. i.e., ' Ericam arboream habitu referens’ ( Richard 1832; p. 338).

Description

(Figs 4, 5, 6). Growth habit mostly trees up to 18 m, sometimes (such as on ultramafic rocks and soils) decumbent and trailing forming shrubs up to 2 × 1 m. Plants with tree-habit usually rather slender and gracile with a somewhat spreading canopy; those in exposed conditions branching at or close to the trunk base, while those growing in dense stands or sheltered sites usually with the lower half devoid of branches. Plants with a decumbent habit usually heavily branched, not rooting on contact with soil. Trunk 1(-4) arising from the ground, 0.10-0.60(-0.85) m d.b.h., mostly erect, slender, weakly flexuose; often basally buttressed, mature trees usually devoid of branches for the first 1-2(-4) m; decumbent plants with scarcely discernible trunk due to branches arising from or close to the base; basal portion of trunks covered with layers of somewhat firm to semi-detached, weakly tessellated, short to long, ± irregularly tabular lengths of subcoriaceous brown-grey to greyish-white bark. Bark early bark chartaceous to subcoriaceous, brown to grey-brown, ± elongate, usually bearing a few transverse cracks (especially on branch flanges and decurrent leaf bases) otherwise remaining firmly attached, margins elongate sinuous, ± entire with scarcely any flaking; old bark similar though more distinctly corky subcoriaceous, often coarsely tessellated or broken in long elongate sections, otherwise remaining firmly attached, if detaching then usually doing so along transverse cracks, and peeling inwards and upwards to leave distinct layers of elongate to coarsely tabular, chartaceous, flakes that are centrally attached, with sinuous margins; upper bark surface usually with much secondary peeling, these flakes similar to primary flakes but more distinctly chartaceous, smaller, narrowly elongate with widely sinuous margins; bark usually crumbling readily in hand, and breaking readily if pulled hard into numerous, small, ± tabular to distinctly irregular flakes. Branches depending on growth habit and situation, numerous, initially arising from close to or at trunk base but as plants mature basally thinning such that branches are retained only in the upper half of the tree; usually rather slender, initially ascending but soon spreading, with apices often distinctly pendulous, branch bases mostly clean, sometimes congested by partially decorticated bark; branchlets numerous, usually rather slender, gracile, initially ascending, soon spreading, terminal growth erect or pendulous; initially bright green or bronze green, sometimes red, ± quadrangular to subterete, glabrescent; new growth sericeous, indumentum initially copious, soon sparse, deciduous, hairs divergent 0.02-0.05 mm long, hyaline to translucent (appearing silvery-white when young maturing silver-grey), apices straight not curled or curved; leaves of branchlets densely crowded along stems and brachyblasts; brachyblasts usually closely spaced, though in vigorous new growth they are sometimes quite widely spaced. Vegetative buds inconspicuous, usually obscured from view by surrounding leaves; at resting stage 0.5-0.8 mm diam. narrowly to broadly ovoid; scales often persistent; (0.4-)1.1 mm long, dark red-brown, broadly ovate, ovate-lanceolate grading through to lanceolate, rostrate to cuspidate; midrib strongly keeled, with one row of 4-8 oil glands on either side of midrib; scales glabrous except for the margins and apex; these densely invested in white, silky hairs. Leaves homophyllous; sessile, lamina surfaces glabrous, margins and the basal, adaxial portion of the midrib hairy (especially on young leaves); densely crowded (particularly toward apices) along branchlets and brachyblasts; initially obliquely ascending, mostly suberect to spreading when mature; lamina (4.0-)13.5(-25.0) × (0.5-)1.1(-1.8) mm, bright green to yellow-green, rarely dark green, adaxial surface often glossy when fresh, drying dull, abaxial surface paler; lamina linear, linear-lanceolate, to narrowly lanceolate, straight or with distal quarter weakly recurved, apex acute, sometimes cuspidate, base attenuate; adaxial lamina surface flat to weakly concave, without obvious oil glands, midrib very slightly raised near base, otherwise scarcely evident, basal portion finely and sparsely covered with deciduous, antrorse-appressed sericeous hairs; abaxial surface flat to weakly convex, glandular punctate, oil glands up to 200; midrib glabrous, usually not evident when fresh, sometimes weakly raised just near base, often not evident when dry but sometimes discernible as a slight groove for entire length; lamina margins initially very finely sericeous, becoming glabrate or glabrous; hairs when present antrorse-appressed, forming a fine, often discontinuous band failing just short of lamina apex, otherwise decurrent along leaf bases. Perules deciduous or persistent, (0.6-)0.8(-1.5) mm, initially squamiform, becoming foliose toward first flower, dark red-brown, broadly ovate, ovate-lanceolate grading through to lanceolate, rostrate to cuspidate; midrib strongly keeled, with one row of 4-12 oil glands on either side of midrib; glabrous except for the margins and apex; these densely invested in white, sericeous hairs. Inflorescence mostly a compact corymbiform to shortly elongate (3-)8(-15)-flowered botryum up to 60 mm long; usually on brachyblasts with the terminal shoot corymbiform or extending as a slightly longer (up to 80 mm long) 6-15-flowered, elongate botryum with flowers usually crowded, terminal portion usually bearing undeveloped flowers and active vegetative growth. Inflorescence axis densely invested with short, weakly divergent silky hairs. Pherophylls foliose ± persistent, 1 per flower; lamina (3.0-)6.7(-7.8) × (0.9-)1.1(-1.4) mm, leaf-like pherophylls bright green (rarely dark green) elliptic, lanceolate to narrowly lanceolate, apex acute, base attenuate; adaxial surface weakly concave to flat, oil glands scarcely evident up to 10; midrib scarcely evident at base only, surface glabrous; abaxial surface weakly convex or flat, oil glands up to 30; midrib scarcely evident at base only, lamina margin glabrescent, hairs as for leaf margins. Pedicels (1.6-)2.7(-3.8) mm long at anthesis, usually elongating slightly after anthesis, terete, usually glabrous, very rarely sparsely covered with divergent to weakly sericeous hairs. Flower buds pyriform to narrowly obconic, apex of mature buds weakly domed to flat, calyx lobes distant, not touching. Fresh flowers when fully expanded (4.1-)6.3(-8.3) mm diam. Hypanthium (1.4-)2.1(-3.2) × (1.9-)2.9(-4.1) mm, with free portion (0.4-)0.6(-1.0) mm long, bright green, bronze-green or yellow-green mottled with red; sharply obconic, apex terminating in a usually dark pink or crimson chartaceous rim bearing five persistent suberect to spreading calyx lobes (rim usually drying dark maroon to maroon-black); external hypanthium surface smooth, glabrous (very rarely glabrescent with basal quarter finely and sparsely covered with minute weakly antrorse hairs); oil glands, conspicuous, ± colourless; ribs not evident when fresh, conspicuous (along with venation) when dry. Calyx lobes 5, suberect to spreading, subcoriaceous, (0.4-)0.7(-1.0) × (0.4-)0.8(-1.0) mm, persistent, orbicular, obtuse to broadly deltoid, red-green, pink or crimson, keel not evident in fresh material, becoming prominent when dried, oil glands conspicuous, ± colourless, margins glabrous or finely ciliate; cilia white. Receptacle green or pink at anthesis, darkening to crimson or dark magenta after fertilisation. Petals 5, (1.4-)2.2(-2.6) × (1.5-)2.2(-2.9) mm, white (often drying yellow), orbicular, suborbicular to narrowly ovate, spreading, apex rounded, margins often incurved, entire or very finely denticulate, oil glands usually not evident when fresh, ± colourless. Stamens (10-)18-24(-34) in 1-2 weakly defined whorls, arising from receptacle rim, filaments white. Antipetalous stamens (2-)3(-5), antisepalous 2-3(-4). Antipetalous stamens outcurved usually with distal portion slightly incurved, on filaments 1.6-2.8 mm long, inner stamens if present, confined to the bases of the outermost antipetalous pair, 0.8-1.2 mm, incurved. Antisepalous stamens shorter than outermost antipetalous stamens, 0.6-1.2 mm, weakly to strongly incurved, rarely erect or outcurved, often in mixtures of both. Anthers dorsifixed, 0.35-0.48 × 0.16-0.24 mm, broadly ellipsoid, latrorse. Pollen white (14.1-)14.6(-17.3) μm. Anther connective gland prominent, pink or pinkish-orange when fresh, drying red to orange, ± spheroidal to pyriform, ± immersed to half of length between anthers, ± coarsely papillate. Ovary (4-)5 locular, each with 16-21(-24) ovules in two rows on each placental lobe. Style 1.5-2.2 mm long at anthesis, elongating slightly after anthesis, white, rarely basally flushed pink; stigma capitate, about 1¼ × the style diam., flat, cream or white, flushing pink after anthesis, surface very finely granular-papillate. Fruits rarely persistent, (1.9-)2.7(-3.4) × (1.8-)2.8(-3.9) mm, glabrous, initially dark green to reddish-green, maturing brown to grey-brown to grey-black; in all types fading with age to pale greyish-white, cupular, barrel-shaped, shortly cylindrical to hemispherical, calyx valves usually erect with the apices incurved, splits concealed by dried, erect, free portion of hypanthium. Seeds 1.00(-1.05) × 0.32(-0.50) mm, usually curved near apex, laterally compressed, 2-3-angled with convex to flattened faces, apex rounded to subacute; base oblique, ± flattened; testa semi-glossy, orange-brown to dark brown, obovoid, oblong, oblong-ellipsoid, or cylindrical and ± curved, surface coarsely reticulate. FL: (Nov-)Dec-Jan(-Mar). FT: Feb-Apr(-Aug). Chromosome Number n = 11II, 2 n = 22 (see de Lange and Murray 2004).

Representative specimens

(99 sheets seen). New Zealand (South Island). Wakamarama Range, Knuckle Hill, P. J. de Lange 4953, 10 Jan 2001, (AK 253376, Duplicate: AD, CHR); Whanganui Inlet, P. J. de Lange 4952, 10 Jan 2001, (AK 289162, Duplicate: AD); Wakamarama Range, Mt Burnett, South Peak, P. J. de Lange 4946, 10 Jan 2001, (AK 289159, Duplicate: AD, MEL); Aorere River, H. Talbot s.n., 15 Dec 1959, (CHR 300594); Golden Bay, Wainui Inlet, Takapou Point, P. J. de Lange 4994, 12 Jan 2001, (AK 289173, Duplicate: AD); Waitui Stream, upper Takaka, W. D. Burke s.n., 23 Nov 1979, (WELTU 13480); Kahurangi National Park, Mt Peel, near source of Trilobite Creek, P. J. de Lange 6329 & G. M. Crowcroft, 16 Jan 2001, (AK 289179); Abel Tasman National Park, Astrolabe Roadstead, Adele Island; P. J. de Lange 5001, 13 Jan 2001, (AK 253380, Duplicate: AD, P); Moutere E.D., Upper Moutere, J. F. F. Hobbs s.n., 18 Aug 2002, (NZFRI 25012); Wangapeka River Road, Rolling River, P. J. de Lange 5082, 21 Jan 2001, (AK 253381, Duplicate: AD); Hope River, Sandy Creek, P. J. de Lange 5085, 21 Jan 2001, (AK 287548, Duplicate: AD); Ngatimoti, Haycock's Hill, R. Wilson s.n., Nov 1964, (OTA 13619); Bryant Range, Hackett Creek, near Whispering Falls, P. J. de Lange 5031 & G. M. Crowcroft, 17 Jan 2001, (AK 286127, Duplicate: AD); Golden Downs, Wakefield, Faulkner’s Bush, P. J. de Lange 5073, 21 Jan 2001, (AK 289193, Duplicate: AD); Nelson Lakes National Park, Speargrass Creek, Speargrass Track, P. J. de Lange 5066, 23 Jan 2001, (AK 289190, Duplicate: AD); Owen Valley East Road, Carrol Creek, P. J. de Lange 5136, 21 Jan 2001, (AK 289201, Duplicate: AD); Buller River, near Owen Junction, P. J. de Lange 5137, 21 Jan 2001, (AK 289202, Duplicate: AD, CHR); Lower Buller Gorge, Buller River, P. J. de Lange 4787 & P. I. Knightbridge, 7 Dec 2000, (AK 288294, Duplicate: AD); D'Urville Island, north of Attempt Hill, P. J. de Lange 5053 & G. M. Crowcroft, 19 Jan 2001, (AK 289185); Pelorus Sound, Mahakipawa Inlet, Moenui, P. J. de Lange 4904, 8 Jan 2001, (AK 288400, Duplicate: AD); Mt Freeth, Queen Charlotte Sound, W. R. B. Oliver s.n., 5 Apr 1931, (WELT SP029535); Cloudy Bay, Rarangi - Port Underwood Road, top of Rarangi Zig Zag Track, P. J. de Lange 5116, 23 Jan 2001, (AK 289198, Duplicate: AD).

Distribution

(Fig. 7). Endemic, New Zealand, South Island (sea level-1600 m a.s.l.). Kunzea ericoides is endemic to the northern South Island north of and including the Wairau and Buller River catchments.

Recognition.

Kunzea ericoides can be easily recognised by its glabrescent, often terminally pendent branchlets (Fig. 6D). The branchlet hairs (Fig. 5A-D, G) are deciduous, consistently divergent, short (up to 0.05 mm), and usually sparse. The leaves of Kunzea ericoides are typically bright green, linear, linear-lanceolate, to narrowly lanceolate, glabrate and mostly crowded on brachyblasts (Fig. 6H). Often the brachyblasts are widely spaced along the branchlets. The hypanthium of Kunzea ericoides is sharply obconic, glabrous (very rarely sparsely hairy), and copiously dotted with conspicuous colourless oil glands. The fruits of Kunzea ericoides are usually glabrous (very rarely sparsely hairy near the base) and are mostly cupular, barrel-shaped, or shortly cylindrical in shape (Fig. 4N). In growth habit Kunzea ericoides varies from a trailing, decumbent shrub on ultramafic substrates to a tall tree (up to 18 m tall) but, irrespective of stature, it typically retains a somewhat spreading to slightly pendulous openly branching habit (Fig. 6B-D). Cytologically Kunzea ericoides has a similar chromosome complement to Kunzea amathicola , Kunzea triregensis and Kunzea sinclairii ( de Lange and Murray 2004). Molecular evidence (rDNA ITS) grouped Kunzea ericoides with Kunzea linearis , Kunzea triregensis , Kunzea robusta (all samples), Kunzea serotina , and Kunzea toelkenii (Table 2 ; see also de Lange 2007; de Lange et al. 2010). However, the rDNA ETS sequence of Kunzea ericoides had one unique cytosine/thiamine mix, shared with Kunzea linearis a cytosine, and, with Kunzea linearis , Kunzea robusta (Mt Egmont samples only), Kunzea salterae , Kunzea serotina and Kunzea toelkenii , a guanine/cytosine mix (Table 2 ; see also de Lange 2007).

Kunzea ericoides is sympatric with Kunzea amathicola , Kunzea robusta and Kunzea serotina and also forms hybrids with them. Of the three, Kunzea ericoides is most frequently sympatric with Kunzea robusta . Both species naturally meet in the Marlborough Sounds where Kunzea robusta , though mainly coastal, is locally common (another occurrence at Totaranui, Abel Tasman National Park, results from the naturalisation from plantings of Kunzea robusta within a camp ground). On the south-eastern coast of D’Urville Island and from about the Tory Channel south toward Rarangi, both species are abundant. The form of Kunzea robusta present in the north-eastern South Island is easily distinguished from Kunzea ericoides as it has extremely hairy branchlets, with the long, silky, antrorse-appressed hairs easily seen by the naked eye or with a 10 × hand lens. Aside from branchlet hairs both species have different foliage colour and leaf shape; Kunzea robusta mostly has dark green leaves that are oblanceolate, broadly oblanceolate to broadly lanceolate with irregularly long sericeous hairs on the margins. Kunzea ericoides has bright green, linear-lanceolate leaves whose margins are sparsely hairy trending toward glabrous (Fig. 4D-H). The hypanthia of both species also differ. In Kunzea robusta the hypanthium is broadly obconic to almost turbinate with the external faces copiously covered in short, antrorse-appressed, sericeous hairs. In Kunzea ericoides the hypanthium is glabrescent to completely glabrous, and sharply obconic. The fruits show much the same differences, Kunzea robusta being broadly obconic to turbinate with the external faces distinctly hairy and Kunzea ericoides mostly cupular, barrel-shaped to shortly cylindrical or sometimes hemispherical and glabrous.

In the north-western part of its range Kunzea ericoides is frequently sympatric with Kunzea amathicola following a line running from the Aorere River west to the Paturau River. Again, both species are easily distinguished due to the very different branchlet indumentum. Kunzea amathicola is distinctly more hairy, with the branchlet hairs long, sericeous, and antrorse-appressed, a marked contrast to the glabrescent branchlets, and short divergent hairs diagnostic of Kunzea ericoides . The leaves, inflorescence type, flowers and fruits of both species are also very different and further distinctions are given in more detail under Kunzea amathicola and in Table 1 . However, two critical characters are briefly mentioned here. The inflorescences of Kunzea amathicola are always elongate botrya, while those of Kunzea ericoides are usually corymbiform (Fig. 4A) though mixtures of corymbiform and shortly elongate botrya are sometimes produced in shaded, stressed or late summer flowering specimens. The pherophylls of Kunzea ericoides are always in mixtures of squamiform and foliose, with the foliose ones ranging from elliptic, lanceolate to narrowly lanceolate, they are never oblong to oblong-obovate like those of Kunzea amathicola . The other major difference is that the leaf margins of Kunzea amathicola are covered in a conspicuous thick, continuous band of long antrorse-appressed, sericeous hairs which reaches the leaf apex. In Kunzea ericoides although marginal hairs are usually present these are hardly conspicuous, tend to be shed as the leaf matures, and they normally form a rather thin, often discontinuous band which does not reach the leaf apex (Fig. 4F-G).

Along the Buller River, at the northern end of Nelson Lakes and in the upper Wairau, Kunzea ericoides is occasionally syntopic with Kunzea serotina . Both species are easily distinguished (Table 1 ), especially as Kunzea serotina has such a distinctive bark type and a pyramidal, columnar, growth habit with obliquely ascending, fastigiate branches. Further, the usual leaf shape of Kunzea serotina is shortly linear-oblanceolate to obovate rather than the longer linear-lanceolate condition of Kunzea ericoides . However, on the ultramafics of the Red Hills and on Mt Dun, Kunzea ericoides tends to be more stunted and in these forms the leaves tend to be half their usual size. While this condition does not appear to have a genetic basis, field distinction can become confusing, especially when such forms grow amongst similarly dwarfed Kunzea serotina specimens. In these situations the branchlet hairs are diagnostic: in Kunzea serotina they are copious, up to 0.08 mm long with curved or curled apices, whereas the branchlets of Kunzea ericoides are glabrescent, with the hairs up to 0.05 mm long and with straight apices (Fig. 5B, D). Flowering material readily separates both species because Kunzea serotina has deciduous, mostly spathulate to spathulate-orbicular, rather than persistent, elliptic, lanceolate to narrowly lanceolate pherophylls, and the oil glands in the petals are yellow, rather than ± colourless.

Ecology.

Although much has been written about the ecology of Kunzea ericoides sens. lat. ( Burrell 1965; Burrows 1973; Wardle 1991; Smale 1994; Smale et al. 1995) most of that information is based on Kunzea amathicola , Kunzea linearis , Kunzea robusta , Kunzea salterae , Kunzea serotina , and Kunzea toelkenii . My observations suggest that Kunzea ericoides is ecologically most similar to Kunzea robusta in that it can be found in a wide variety of habitats from early stage seral shrubland (Fig. 6A) through to tall forest, and it has a similar growth habit. However, it attains a much higher altitudinal limit than Kunzea robusta , having been collected during this study at 1600 m a.s.l. on the northern slopes of Mt Peel, Kahurangi National Park, north-west Nelson. In montane areas it is frequently found within north-facing canopy gaps developed within montane black beech ( Fuscospora solandri (Hook.f.) Heenan et Smissen) and mountain beech ( Fuscospora cliffortioides (Hook.f.) Heenan et Smissen) forests, often close to the upper tree limit for these species in the Richmond Range and parts of north-west Nelson. The species is also commonly encountered in coastal forest, though rarely on sand dunes, and it can be a conspicuous tree of lowland areas, especially along river flats and on outwash gravels within the Waimea Plain and on sections of the northern bank of the Buller River.

No obvious substrate requirement is evident. It appears to avoid permanently waterlogged soils and peat and it is scarce from wetlands, though it may at times be common in the vegetation bordering these habitats. Free draining soils and recent alluvium is commonly colonised, as is open ground within lowland to upper montane forests. On the extensive karstfield of north-west Nelson Kunzea ericoides is often prominent, especially in places where there has been a history of logging, mining, farming or frequent fires. Kunzea ericoides is also a common component of the ultramafic areas of D’Urville Island, Mt Dun, the Red Hills and upper Takaka.

Kunzea ericoides is an important primary tree coloniser of formerly cleared ground in many parts of its range. In these situations, perhaps more than any other, the dense leaf litter produced by the often closely growing trees is ideal for a wide range of terrestrial orchids (especially of the genera Acianthus R.Br., Caladenia R.Br., Corybas Salisb., Gastrodia R.Br., and Pterostylis R.Br.), and fungi (see McKenzie et al. 2006), while the bark is often colonised by mosses such as Macromitrium Brid. spp., Cryphaea tenella Müll.Hal., Distichophyllum pulchellum (Hampe) Mitt., and Weymouthia cochlearifolia ( Schwägr.) Dix, and by liverworts of the genera Frullania Raddi, Lejeunea Lib. and Metzgeria Raddi. Kunzea ericoides bark also supports a diverse array of lichens in the following genera; Coccocarpia Pers., Heterodermia Trevis., Pannaria Delise ex Bory, Parmotrema A.Massal., Pseudocyphellaria Vain., Sticta (Schreb.) Ach. and Ramalina Ach. The upper branches and branchlets are also frequently parasitised by the dwarf mistletoe Korthalsella salicornioides (A.Cunn.) Tiegh. and, less commonly, green mistletoe ( Ileostylus micranthus (Hook.f.) Tiegh.). Kunzea ericoides -dominated shrubland and forest also provides an important and at times critical habitat for a range of geckos in the endemic genera Mokopirirakau Nielsen et al. 2011, Naultinus (Gray, 1842), and Woodworthia Garman 1901 (R. Hitchmough pers. comm.).

Hybridism.

Kunzea ericoides naturally hybridises only with Kunzea amathicola , Kunzea robusta and Kunzea serotina . The most common of these hybrids is Kunzea ericoides × Kunzea robusta , which is abundant on the south-eastern side of D’Urville Island (especially around Katherine Bay), and along the eastern side of the Marlborough Sounds, particularly east of Picton and south of the Tory Channel to about Rarangi. These areas comprise some of the first sites of European settlement in New Zealand, prior to which they were once heavily populated by Maori ( Buick 1976; de Lange et al. 2005). Both cultures extensively modified these landscapes and even in modern times much of this area has been repeatedly burned. These are ideal conditions for hybridism, and in the case of both Kunzea ericoides and Kunzea robusta it has helped create and maintain an extensive introgressed hybrid swarm.

Recognition of Kunzea ericoides × Kunzea robusta in the field and in the herbarium is generally easy because both species have such different branchlet hairs. Hybrid plants can usually be recognised by the presence of mixtures of long, silky, antrorse-appressed and very short divergent hairs. Further, Kunzea ericoides × Kunzea robusta hybrids often have a distinctly pale glaucous sheen to their usually yellow-green leaves. Similar plants were produced in the experimental F1 crosses Kunzea ericoides ♀ × Kunzea robusta ♂ and Kunzea robusta ♀ × Kunzea ericoides ♂ and these proved to be fully fertile ( de Lange et al. 2005). In most instances the hybrid can be easily recognised but because hybrids are fully fertile, an often bewildering array of introgressants can be found in sites of prolonged disturbance, in some cases almost to the exclusion of either parent. Recognition of hybrids within such populations can at times be difficult. For example, in those hybrids trending toward Kunzea ericoides there is a progressive loss of the long, antrorse-appressed sericeous branchlet hairs diagnostic of Kunzea robusta . In some examples where the branchlet hairs are virtually dominated by short divergent hairs, a hybrid ancestry may still be elucidated by diligent searching, particularly along the branchlet axis immediately opposite active leaf buds and emergent leaves where a few of the longer, antrorse-appressed sericeous type diagnostic of Kunzea robusta are usually retained as sparse patches. In pure Kunzea ericoides these are mostly all soon shed. One of the last Kunzea robusta traits to be lost is the presence of antrorse-appressed, silky hairs on the external surface of the hypanthia, allowing the hybrid origin of specimens in all other respects matching Kunzea ericoides to still be elucidated. Branchlet hairs, or rather their relative abundance also serves to help distinguish introgressants trending toward pure Kunzea robusta such that apparently pure specimens of Kunzea robusta prove on careful examination of the branchlets to be glabrescent and completely dominated by short, divergent hairs. For Kunzea ericoides at least, the branchlet hairs seem to be a long-lived trait traceable in any hybrid swarm it may form. In north-west Nelson from about Golden Bay and the Whanganui inlet north, Kunzea ericoides and Kunzea amathicola are commonly syntopic and hybrids are frequent in the more heavily modified lowlands and roadsides of this area. Like the Kunzea ericoides × Kunzea robusta hybrid, the branchlet indumentum enables recognition because it comprises mixtures of both hair types. The inflorescences of Kunzea amathicola × Kunzea ericoides hybrids are also in mixtures of mostly elongate (typical of Kunzea amathicola ) and some subcorymbiform to corymbiform botrya (typical of Kunzea ericoides ). The pherophylls tend to be rather variable in length and size but they are mostly lanceolate to linear-lanceolate like Kunzea ericoides . The leaf margins of Kunzea amathicola × Kunzea ericoides are also distinctive. Initially they are hairy but, like Kunzea ericoides , the hairs are progressively shed during leaf maturation. Further, hairs rarely (if ever) meet at the leaf apex.

Kunzea ericoides × Kunzea serotina is much less common, because the ranges of both species rarely overlap. This hybrid is mostly confined to the upper Buller River and within the Barnicoat Range and Hackett areas of eastern Nelson where the usually montane Kunzea serotina extends down into lowland areas and so abuts the main habitats of Kunzea ericoides . These are also areas where road construction and maintenance has significantly altered the surrounding indigenous vegetation allowing these species to meet and hybridise. Kunzea ericoides × Kunzea serotina is easily recognised by the erect, somewhat open, sub-pyramidal growth habit, short, weakly fastigiate branchlets, and bright yellow-green, red-tinged leaves (all features of Kunzea serotina ). However, as with Kunzea ericoides , the leaves tend to be linear-lanceolate, though sometimes quite broadly so. Branchlet indumentum is not particularly useful because both parent species have divergent hairs, though in most examples the hybrid tends to be, like Kunzea serotina , distinctly hairy. However, rare glabrescent examples suggest that introgressive hybridisation toward Kunzea ericoides is occurring at some sites. The pherophylls of Kunzea ericoides × Kunzea serotina , like those of Kunzea serotina , are not persistent but are mostly shed during flower maturation. Further, the pherophylls of the hybrid are pandurate to elliptic (never spathulate like Kunzea serotina or narrowly elliptic, lanceolate to narrowly lanceolate like those of Kunzea ericoides ). The flowers of Kunzea ericoides × Kunzea serotina offer another point of recognition. Like Kunzea serotina they tend to have more obvious oil glands than is usual for Kunzea ericoides , and while those of Kunzea ericoides are normally colourless, those of the hybrid vary from colourless through to pale yellow, the latter of which is the usual condition of Kunzea serotina .

Vernacular names.

Although now universally known as ‘kanuka’, the name recorded for Kunzea ericoides from the Nelson area during Dumont d’Urville’s second voyage was ‘manuoea’ ( Richard 1832). Based on other specimens lodged at P(!) and elsewhere this species was also known as ‘manuka’, ‘titire’ and ‘atitire’ (for a discussion on the names ‘titire’ and ‘atitire’ see Kunzea robusta ).

Conservation status.

Kunzea ericoides is a widespread and abundant species throughout its northern South Island range and is lited as 'Not Threatened’ by de Lange et al. (2013b).