Kunzea toelkenii de Lange, 2014

de Lange, Peter J., 2014, A revision of the New Zealand Kunzea ericoides (Myrtaceae) complex, PhytoKeys 40, pp. 1-185 : 49-54

5. Kunzea toelkenii de Lange sp. nov.

A K. tenuicaulis habitu late expanso (usque ad 6 m lato), brevi (usque ad 4 m alto), valido multicauli, caulibus pertortis torsivis et flexis; surculibus frequentibus perfecte prostratibus ad 4 m e basi trunci expositis; ramis et ramulis superis pendulis, faragine pilorum longorum leniter flexuorum antrorum et brevium divergentium crisporum circinatorum; seriebus rDNA ITS et ETS differt.

Holotypus

(Fig. 25). New Zealand (North Island). Bay of Plenty, State Highway 2, near Thornton (Wahieroa Dunes), Walker Road, 37°58'27"S, 176°50'11"E, 10 m a.s.l. 'Dominant, growing with Muehlenbeckia complexa , Lupinus arboreus , boxthorn and Pyrrosia eleagnifolia as sparse associates. Multi-trunked shrubs to small trees up to 4 × 4 m’. P. J. de Lange 5322 & R. O. Gardner, 25 Oct 2001, AK 255350! Isotypes: AD! BM! CHR! NZFRI! P!

Etymology.

The specific epithet toelkenii honours Australian Kunzea expert Hellmut Toelken (1939-).

Description

(Figs 26, 27, 28). Growth habit shrubs up to 4 × 6 m; ‘juveniles’ usually prostrate and trailing up to 4 m diam., often flowering, taking 2-4 years to develop several, usually central, ascending branches; ‘adults’ forming widely spreading (up to 2 m diam.), characteristically flat-topped shrubs, with pendulous branches and branchlets; branches confined to upper 30-50% of shrub, basal 50-70% usually completely devoid of branches and vegetative growth, sometimes bearing completely pendulous growth; trunk bases usually bearing epicormic, prostrate growth spreading up to 4 m diam. from point of origin; this growth occasionally layering and producing further trunks. Trunk (1-)6(-10), ascending to suberect, serpentine, highly contorted, twisted, bent, and spiralled, 0.10-0.25(-0.40) m d.b.h.; mostly arising from the top of a broad rootstock, and also from layered masses of prostrate epicormic growth; in all cases basal portions of trunks covered with numerous semi-detached, sinuous, rather corky, lengths of bark. Bark early bark firmly coriaceous, grey or grey-brown, ± elongate, initially with few transverse cracks, soon becoming heavily cracked (into highly irregular pieces with rather sinuous margins (especially on branch flanges and decurrent leaf bases) but remaining firmly attached; old bark similar though more distinctly coriaceous-corky, upper surface often deeply corrugated and cracked but not peeling; detaching inwards readily but usually remaining centrally firmly attached; margins sinuous to lunate, often highly irregular and frayed, rarely shortly tabular; early and old bark flakes firm, scarcely crumbling in hand. Branches of trunks numerous, usually confined to the upper 30-50% of trunk; widely spreading, ± serpentine, flexuose, often pendulous and interwoven; branchlets numerous, slender, usually apically pendulous, very leafy, with few to many brachyblasts; those of epicormic growth, straight not flexuose or serpentine, prostrate or pendulous if arising from basal half of trunk, widely spreading; in all cases quadrangular, sericeous, indumentum copious; hairs persistent, of two types: long, appressed often flexuose hairs up to 0.26 mm long, and smaller divergent hairs, with strongly curled and spiralled apices 0.04-0.10(-0.18) mm hyaline to translucent (appearing white when young maturing grey). Vegetative buds conspicuous; at resting stage 1.2(-1.8) mm diam.; scales scarious, deciduous, (0.4-)0.9(-1.2) mm long, brown to red-brown, broadly ovate to ovate-deltoid, apex obtuse to rounded; midrib prominent, strongly keeled in upper half, occasionally prolonged to a long cuspidate tip, lateral veins usually absent, oil glands usually absent, upper half of scale margins, keel, and keel apex ciliate. Leaves well spaced along branchlets, spreading, patent to recurved; lamina (2.6-)5.7(-8.5) × (0.6-)1.6(-2.5) mm, dark glossy green or bright-green, margins and base usually flushed red; spreading, obovate, clavate, to broadly oblanceolate; weakly to strongly recurved from about 30-50% of total length; apex sharply acute to apiculate, base attenuate; adaxial surface concave very rarely flat, finely glandular punctate; oil glands up to 280, more evident when dry; midrib slightly raised near base, otherwise not evident for rest of length, finely covered in deciduous, sericeous, antrorse-appressed, hairs in lower half otherwise glabrous; abaxial surface convex, glandular punctate, oil glands up to 180, more evident when dry; midrib raised for most of length, glabrous; lamina margin finely to densely sericeous, hairs weakly flexuose, antrorse, subantrorse to spreading, up to 0.5 mm long, hyaline to translucent, appearing white to naked eye, aligned in 1-2 uninterrupted rows meeting just short of leaf apiculus. Perules scarious, persistent, (0.5-)1.0(-1.8) mm; basal ones dark brown to red-brown, broadly ovate, ovate, ovate-rostrate, to lanceolate, without oil glands, margins involute, ciliate, midrib strongly keeled with 1-2 usually finely ciliate lateral veins on each side, keel prolonged as a short to long, deciduous, obtuse-tipped, densely ciliate, cuspidate apiculus; remaining perules similar but smaller, chartaceous, (0.3-)0.8(-1.0) mm long. Inflorescence a compact, (1-)7(-10)-flowered corymbiform botryum up to 40 mm long, mostly borne on alternate, distinctly spiralled, basally densely leafy, brachyblasts up to 12 mm long; inflorescences at the ultimate branchlet terminus uncommon (except in trailing epicormic growth), if present, often rather elongated (up to 80 mm long) and bearing well developed terminal vegetative growth, often with the uppermost flowers in elongated shoots male. Inflorescence axis densely invested with divergent hairs. Pherophylls deciduous (falling very early), initially foliose, soon squamiform, tightly clasping pedicel or spreading, 0.4-1.6 mm long, foliose pherophylls green to bronze-green, shortly lanceolate to obovate, squamiform pherophylls amber-brown to brown, narrowly deltoid to ovate, both types adaxially deeply concave, margins and apex finely ciliate, grading into leaves at inflorescence axis apex. Pedicels (1.6-)2.9(-3.8) mm long at anthesis, usually elongating slightly after anthesis, terete, copiously invested with short, divergent to subantrorse, silky hairs. Flower buds bluntly clavate to obconic, rarely pyriform, apex flat prior to bud burst with calyx valves not meeting. Fresh flowers when fully expanded (3.6-)6.8(-9.0) mm diam., often functionally male toward end of flowering season. Hypanthium (1.7-)2.4(-3.2) × (2.8-)3.6(-4.3) mm, with free portion 0.6-0.9 mm long, green, dark green or red-green; obconic to funneliform, terminating in light-green to pink-green membranous rim bearing five persistent calyx lobes; surface smooth when fresh somewhat wrinkled when dry, with weakly defined ridges leading up to calyx lobes; sparingly dotted with pink or colourless oil glands otherwise with basal half finely and rather densely puberulent with areas leading to calyx lobes distinctly glabrescent; hairs silky, spreading, subantrorse to antrorse-appressed, often with smaller divergent hairs underlying larger appressed ones. Calyx lobes 5, upright (not spreading), submembranous, (0.8-)1.0(-1.2) × (0.7-)1.0(-1.2) mm, persistent, ovate, broadly ovate to ovate-deltoid, of uniform thickness in transverse section, without keel, often uniformly green, otherwise with central portion of lobe darker green or pinkish green, with margins usually pale green to green flushed with pink, surface somewhat glandular punctate, oil glands inconspicuous, ± colourless, otherwise glabrous except for distinctly spreading, ciliate margins. Receptacle usually pink at anthesis, consistently darkening to dark magenta or maroon-black after fertilisation. Petals 5(-6), 1.5-1.9(-2.8) × 1.5-1.9(-2.6) mm, white, orbicular to very broadly ovate, apex obtuse to rotund, margins ± entire, often finely folded or crimped 1-5 times, oil glands colourless. Stamens 20-36(-50) in 1(-3) weakly defined whorls, arising from receptacular rim, filaments white. Antipetalous stamens (2-)3(-6), antisepalous (1-)3(-8). Outermost antipetalous stamens weakly incurved or outcurved, on filaments 1.2-3.6 mm long, inner stamen if present, 0.8-1.2 mm, incurved or outcurved, a further 1-3 stamens, of similar length are very rarely present at the base of the outermost antipetalous pair. Antisepalous stamens usually shorter than outermost antipetalous stamens, sometimes of comparable length, generally 0.6-3.2 mm, mostly incurved, outcurved or in mixtures of both. Anthers dorsifixed, 0.06-0.09 × 0.05-0.08 mm, testicular-oval to testicular-ellipsoid, latrorse. Pollen white (12.2-)13.6(-17.8) μm. Anther connective gland prominent, pale lemon to pink when fresh, drying yellow to pale orange, spheroidal, finely papillate. Ovary absent in males flowers, otherwise 3-4(-5) locular, each with 12-20(-24) ovules in two rows on each placental lobe. Style absent in male flowers, otherwise 1.0-1.4(-1.8) mm long at anthesis, elongating slightly after anthesis, white; stigma capitate, scarcely wider than style, flat, greenish-white, cream or pale pink, surface papillate. Fruits rarely persistent, (2.1-)2.6(-3.0) × (2.5-)3.0(-3.7) mm, light brown to grey, obconic, broadly obconic, to cupular, splits concealed by dried, suberect to erect, free portion of hypanthium. Seeds 0.50-1.00(-1.02) × 0.52-0.60(-0.68) mm, oblong, oblong-obovate, curved near apex, laterally compressed, 2-3-angled with convex to flattened faces, apex rounded to subacute; base oblique, ± flattened; testa semi-glossy, amber, orange-brown to brown, surface coarsely reticulate. FL: (Sep-)Oct-Nov. FT: Oct-Sep. Chromosome Number n = 11II, 2 n = 22 (see de Lange and Murray 2004).

Representative specimens

(16 sheets seen). New Zealand (North Island). State Highway 2, near Seacombes Canal, P. J. de Lange 5324 & R. O. Gardner, 25 Oct 2001, (AK 287042, Duplicate: AD); State Highway 2, Walker Road, P. J. de Lange 5314, 29 Sep 2001, (AK 287049); State Highway 2, Walker Road, P. J. de Lange 5323 & R. O. Gardner, 25 Oct 2001, (AK 287045, Duplicate: CHR); 1.75 km east of Rangitaiki River Mouth, Thornton Wildlife Management Reserve, eastern end of lagoon, P. B. Cashmore s.n., 7 Jun 2007, (AK 299633); 3.3 km East of Rangitaiki River Mouth, near Whakatane Airport Buildings, P. B. Cashmore s.n., 7 Jun 2007, (AK 299634); Whakatane, Piripai Spit, East of Coastlands Subdivision, P. B. Cashmore s.n., 12 Jul 2007, (AK 300903); Ohiwa Harbour, Whangakopikopiko (Tern Islet), P. J. de Lange 7247 & P. B. Cashmore, 5 Dec 2007, (AK 301682, Duplicate: CHR).

Distribution

(Fig. 7). Endemic, New Zealand, North Island, Bay of Plenty (2-10 m a.s.l.). Kunzea toelkenii is known from a small strip of sand dune country (the Wahieroa Dunes) between the eastern bank of the Tarawera River mouth and the west bank of the Rangitaiki River mouth, near Thornton, and from another small population on a barrier sandspit island, Whangakopikopiko (Tern Islet), at the mouth of the Ohiwa Harbour. The current distribution is undoubtedly relict; the habitats occupied are remnants of indigenous woody sand dune vegetation that formerly extended as far west as Papamoa. Although I have been unable to find any supporting herbarium evidence, locals recollect that much of the sand country between Papamoa and Pikowai beach once supported dense 'kanuka [ Kunzea ] shrublands’ (G. Wrigley pers. comm.). From the descriptions given by these people which include such phrases as 'tortured growths....pendulous shrubs.......... suckering stems’ it is quite likely that Kunzea toelkenii was the species involved, and that it was once a locally important species of the Bay of Plenty sand dune country.

Recognition.

Kunzea toelkenii is recognised by its uniquely suberect, sprawling growth habit, typically extensive suckering (Fig. 28A-C), by its mixed branchlet hairs (Fig. 27A-C), tendency to produce late season functionally male flowers (Fig. 28F), and also by its restriction to active sand dunes (Fig. 28A-B). Further differences are given in Table 1 . The distinctiveness of Kunzea toelkenii was probably first recognised in the mid 1980s by the late Mr Derek Gosling of Whakatane who cultivated it, while the unusual ecology of the species was first noted and described in detail by Smale (1994 as Kunzea ericoides var. ericoides ).

Kunzea toelkenii is distinguished from the other New Zealand members of the Kunzea ericoides complex by its unique growth habit, in particular the spiralled, often tortured multi-trunked (Fig. 28C) growth habit, and ability of the trunk base to produce numerous, completely prostrate, widely spreading epicormic branches. This growth habit has previously been interpreted as habitat induced ( Smale 1994). However, cultivation trials initiated by Mr Gosling showed that the distinctive multi-trunked shrub habit has a genetic basis. In cultivation, seedlings are completely prostrate but within 2-4 years of germination most develop one or more suberect trunks. Interestingly, Smale (1994) described the same development (what he termed 'semi-prostrate candelabra’ habit) in specimens as 'early as 6 years’ of age. The ability of Kunzea toelkenii to sucker from the trunk base is similar to the growth habit of five of the seven endemic Australian members of the Kunzea ericoides complex ( de Lange 2007). However, while these Australian species all possess a distinctly bulbous, fire-resistant lignotuber (with at least one of these species, Kunzea leptospermoides F.Muell. ex Miq. also having a rhizomatous habit), such structures are absent in Kunzea toelkenii .

The branchlet indumentum of Kunzea toelkenii is also distinctive, comprising mixtures of sparse, long antrorse-appressed, somewhat flexuose hairs, and more numerous, somewhat shorter, divergent, often curled and spiralled hairs (Fig. 27C). No other New Zealand Kunzea species has such distinctive curled and spiralled divergent hairs, although mixtures of appressed and divergent hair types is a feature common to the hybrid Kunzea robusta × Kunzea tenuicaulis . Although a hybrid origin for Kunzea toelkenii seems likely, and experimental examples of Kunzea robusta × Kunzea tenuicaulis (AK 286145) are very similar to it, experimental hybrids of this cross lacked the curled and spiralled branchlet hairs and distinctive growth habit of Kunzea toelkenii .

Ecologically, Kunzea toelkenii is further distinguished as the only member of the Kunzea ericoides complex truly endemic to sand dune systems (cf. Kunzea amathicola described later). Within its sand dune habitat Kunzea toelkenii is known to occur sympatrically only with Kunzea robusta and even then scarcely so (e.g., Coastlands, Whakatane (P. B. Cashmore s.n., (AK 300902)) and Whangakopikopiko (Tern Islet), Ohiwa Harbour (P. J. de Lange 7248 & P. B. Cashmore, (AK 301683)). However, this pattern more probably reflects past land clearance patterns because elsewhere in the Bay of Plenty Kunzea robusta is widespread, with a range that extends to sand dunes, e.g., Waihi Beach, Matakana Island.

A final peculiarity is the tendency of Kunzea toelkenii , uniquely amongst the New Zealand species, to produce functionally male flowers (Fig. 28F). In most cases these flowers had almost vestigial, non-functional stigmas, though occasionally even these are absent. Such flowers have been described for New Zealand examples of Leptospermum scoparium ( Primack and Lloyd 1980) and are now known from at least five other Australian species of that genus ( Andersen 1990; O’Brien 1994) but as far as I am aware they have not been reported previously for Kunzea . As with the Leptospermum examples studied (see in particular Andersen 1990), functionally male flowers appear toward the end of the flowering season. In Kunzea toelkenii they appear to be consistently produced in wild and cultivated plants, though in varying degrees and not necessarily on every plant.

Kunzea toelkenii has the same ITS and ETS sequences (Table 2 ) as Kunzea serotina ( de Lange 2007; de Lange et al. 2010). No variable sites are present in the ITS sequence, while the ETS sequence of both species, together with Kunzea ericoides , Kunzea robusta (Mt Egmont samples only) Kunzea salterae and Kunzea tenuicaulis , share a guanine/cytosine mix at ETS alignment position 232 ( de Lange 2007). Otherwise the ETS asequence of Kunzea toelkenii shares an adenine nucleotide with Kunzea salterae , Kunzea serotina , and Kunzea tenuicaulis ( de Lange 2007).

Ecology.

The ecology of Kunzea toelkenii was described in detail by Smale (1994 as Kunzea ericoides var. ericoides ). The extant consolidated and semi-consolidated foredune and dune swale habitats of Kunzea toelkenii near Thornton are estimated to be less than 700 years old ( Pullar and Selby 1971), while Whangakopikopiko (Tern Islet), a barrier-spit island at the Ohiwa Harbour mouth, is probably even younger. Kunzea toelkenii is the dominant woody species within these habitats and associated species are scarce. Smale (1994) recorded 17 vascular flora associates from the Thornton site, the majority of which were exotic naturalised species, and only five were woody trees or shrubs. Of the naturalised species at Thornton, Smale (1994) identified boxthorn ( Lycium ferocissimum Miers) as potentially invasive and a possible threat to Kunzea toelkenii . He also observed that the Kunzea toelkenii population appeared to form a single distinct cohort with a mean age of 45 years, though specimens up to 70 years of age were occasionally encountered, and that the stands sampled appeared to have arisen through invasion of open sand dune vegetation, possibly after fire had removed the previous vegetation cover. Smale (1994) was of the opinion that the Kunzea stands (here Kunzea toelkenii ) would replace themselves indefinitely, partly because Thornton is so isolated from other seed sources of potential successors. A similar, though less dense population to that seen at Thornton is present at Whangakopikopiko (Tern Islet), and there the impression is of a very recent establishment. If so, this suggests that at some stage Kunzea toelkenii was present on the adjoining sand spits of Ohope and Ohiwa, all now extensively developed and housed, and from where only scattered individuals of Kunzea robusta are now known.

Hybridism.

Within its habitat Kunzea toelkenii very rarely associates with other Kunzea species and thus far wild hybrids have not been found. Nevertheless experimental hybrids were readily produced using Kunzea toelkenii as pistillate or staminate parent ( de Lange et al. 2005, as Kunzea aff. ericoides (d)).

Vernacular name.

No specific vernacular appears to be in use for Kunzea toelkenii .

Conservation status.

As Kunzea aff. ericoides (a) (AK 255350; Thornton) Kunzea toelkenii is appropriately assessed by the New Zealand Threatened Vascular Plant Panel ( de Lange et al. 2013b) as 'Acutely Threatened/Nationally Vulnerable’, qualified 'Range Restricted (RR)'.