Dracophyllum arboreum
Common name
Chatham Island grass tree, tarahinau
Synonyms
Dracophyllum latifolium var. ciliolatum Hook. f.; Dracophyllum scoparium var. major Cheeseman
Family
Ericaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Trees & Shrubs - Dicotyledons
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.
DRAARB
Chromosome number
2n = 26
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). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By 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.
2012 | At Risk – Naturally Uncommon | Qualifiers: IE, Inc
Previous conservation statuses
2009 | At Risk – Naturally Uncommon | Qualifiers: IE
2004 | Range Restricted
Brief description
Tree up to 18 m tall (known only from the Chatham islands), leaves, green, grass-like of two types (broad juvenile and narrow adult), with adult specimens bearing white flowers borne in spikes and often partially obscured by persistent hard and sharp–tipped floral bracts
Distribution
Endemic. Chatham Islands (Rekohu (Chatham), Rangiuria (Pitt ) and Rangatira (South East) Islands)
Habitat
Dracophyllum arboreum is an important component of Chatham Island forest, especially away from the coast and on the deeper peaty soils. In these sites it is often the dominant tree. Sometimes found in restiad bog where it overlaps with and often forms hybrids with D. scoparium Hook.f.
Features
Tree 4–18 m tall. Bark on old branches greyish–brown to brown, finely fissured, young stems yellowish to reddish brown. Leaves dimorphic (juvenile and adult); juvenile leaves crowded at tips of branches, spreading; lamina sheath 9.0–17.0 × 7.4–16.6 mm, yellowish to light green, coriaceous, tapering and margin ciliate or ciliate in upper half only; lamina subcoriaceous to coriaceous, 100–220 × 10–18 mm, linear–triangular, surfaces glabrous, margins densely pubescent; adult leaves spreading; lamina sheath 6–12 × 4–12 mm, light green, membranous, tapering with a ciliate margin; lamina 25–90 × 1–2 mm, linear to linear–triangular, surfaces glabrous with a tuft of scabrid hairs at base of adaxial surface; margins densely pubescent. Inflorescence a terminal spike on lateral branchlets, shorter than leaves, erect to drooping, dense, 15–38 mm long, linear–oblong; inflorescence bract overtopping the flower, 18–20 × 3–5 mm, subulate, surfaces glabrous, adaxial surface pubescent at base, margins ciliate. Flowers 4–9, sessile; flower bract persistent, overtopping flowers, foliose, 5.5–9.0 × 2.5–3.0 mm, ovate to broadly ovate, surfaces glabrous, adaxial surface with a tuft of scabrid hair at apex; margins ciliate. Sepals 4.0–7.0 × 2.5–3.0 mm, ovate lanceolate, longer than corolla tube, surfaces glabrous with the top half pubescent; margins ciliate. Corolla white; corolla tube 4–5 × 2.5–3.0 mm, cylindrical; corolla lobes reflexed, 2.0–2.4 × 1.0–2.0 mm, triangular, shorter than corolla tube; apices acute; adaxial surface papillate. Stamens inserted on corolla tube in upper third, filaments 0.3–1.0 mm long; anthers included, 0.3–0.4 mm long, oblong, light yellow. Ovary 1.7–2.0 × 1.0–2.0 mm, obovate; glabrous, apex round; nectary scales, 1.0–1.2 × 0.5–0.8 mm, oblong, apices irregularly toothed; style included, 2.0–2.5 mm long, glabrous; stigma capitate. Fruit sessile, 1.2–1.5 × 1.0–1.5 mm, oblong, apex round, dark brown, glabrous. Seed 0.6–0.65 mm long, ovoid, yellowish brown, testa slightly reticulate.
Similar taxa
Dracophyllum arboreum is a distinctive and easily recognised species, well marked by its tree-habit (growing up to 18 m tall), long and broad juvenile leaves with adult leaves densely ciliated on the margins and pubescent at the base, persistent hard and sharp–tipped bracts that are broad with long white hairs on the adaxial surface, and by the corolla tube 4–5 mm long and shorter than the sepals (and with long cilia on the lower surface).
Dracophyllum arboreum can be confused with D. scoparium, especially when it grows on the margins of the restiad bogs D. scoparium favours. From D. scoparium, D. arboreum differs by its taller tree habit, much larger, yellow-green rather than bronze-green to red-green, juvenile foliage, which is often carried through as reversion shoots on adult trees, and by the upper leaf surface which is pubescent rather than tomentose. Dracophyllum scoparium is confined to restiad bogs where it forms shrubs up to 2 m high. In disturbed habitats it frequently hybridises with D. arboreum.
Flowering
Throughout the year
Flower colours
Red/Pink, White
Fruiting
Throughout the year
Life cycle
Minute seeds are wind dispersed (Thorsen et al., 2009).
Propagation technique
Can be grown from fresh seed. However tricky to maintain. An attractive species that flourishes best in acidic, permanently damp but not water logged peaty soils.
Threats
Reasonably secure and regarded as not threatened. However populations off protected land are vulnerable to clearance for farmland and fires. Many populations in the northern two thirds of the main island are remnant stands on farmed land and are in decline. Despite this tarahinau is abundant over much of the southern table lands and on Pitt Island.
Etymology
dracophyllum: Dragon leaf, from its likeness to the dragon tree of the Canary Islands
arboreum: Tree-like
Where To Buy
Not commercially available.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (4 October 2012). Description adapted from Venter (2009) supplemented by authors own observations and measurements.
References and further reading
Venter, S. 2009: A taxonomic revision of the genus Dracophyllum Labill. (Ericaceae). Unpublished Phd Thesis, Victoria University of Wellington, Wellington.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Dracophyllum arboreum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/dracophyllum-arboreum/ (Date website was queried)