Species

Ixerba brexioides

Etymology

Ixerba: an anagram of brexia
brexioides: like a Brexia, a South African shrub

Common Name(s)

Tawari, whakou (flowers)

Current Conservation Status

2012 - Not Threatened

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

2009 - Not Threatened
2004 - Not Threatened

Authority

Ixerba brexioides A.Cunn.

Family

Strasburgeriaceae

Brief Description

Bushy tree bearing narrow thick serrated dark green leaves and clusters of white flowers with a prominent green centre inhabiting the upper North Island. Leaves 6-16cm long by 1-4cm wide. Flowers 2.5-3.5cm wide. Fruit a green capsule, splits to reveal the black seeds on a fleshy orange and white base.

Flora Category

Vascular - Native

NVS Species Code

IXEBRE

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.

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

None

Distribution

Endemic. New Zealand, North Island ( widespread from about Kaitaia south to Waitomo, Paeroa Range and Te Urewera).

Habitat

Often but not exclusively an associate of kauri (Agathis australis) forest. Also common in montane cloud forest. Prefers shaded or sheltered sites, often near streams and in permanently damp ground. Can be locally abundant in some areas but otherwise it is rather sporadic in its occurrences,

Features

Small tree up to 10 m tall with spreading crown. Trunk 0.2-0.4 m diam., bark dark brown to grey-brown. Branchlets, leaves and inflorescences clade in fine pubescence when young. Petioles, stout, fleshy, 20 mm long. Leaves yellow-green to dark-green above, paler beneath, somewhat fleshy, distinctly leathery, 60-160 x 10-40 mm, lanceolate to elliptic or oblanceolate, apex acute to subacute, margins bluntly and coarsely serrated. Apex of each serration surmounted with a small gland. Juvenile leaves often reddish, linear-lanceolate. Inflorescence a terminal subumbellate 5-10-flowered panicle. Flowers 25-35 mm diam, furnished with plenty of nectar. Sepals broad-ovate, downy, 5-6 mm long; petals white, obovate-spathulate, clawed, 15-20 mm long, inserted below a 5-lobed disc; stamens 5 exserted, alternating with disc lobes; style twisted, 5-grooved. Capsule leathery, broadly ovoid, 5-celled, seeds orange, 5 mm long, very glossy.

Similar Taxa

A very distinctive tree easily recognised by the leathery, somewhat fleshy, lanceolate leaves, whose serrations are glandular-tipped, large, showy, white flowers, and distinctive capsules which split to reveal rather large glossy black seeds.

Flowering

(September-) October-November (-December)

Flower Colours

White

Fruiting

November - January (-March)

Propagation Technique

Difficult to grow. It has been suggested that the species is mycorrhizal, and there is some evidence that if planted in association with Griselinia littoralis, Ixerba grows very easily.

Threats

Not Threatened

Chromosome No.

2n = 50

Endemic Taxon

Yes

Endemic Genus

Yes

Endemic Family

Yes

Life Cycle and Dispersal

Arrilate seeds are dispersed by frugivory (Thorsen et al., 2009).

Taxonomic notes

Ixerba has been placed in a range of families. Allan (1961) placed it in the Escallionaceae, however this placement was at best doubtful, and so it was placed in 2008 into its own family the monogeneric Ixerbaceae. it was then, for a very short time New Zealand's only endemic vascular plant family. However, in 2009 the Ixerbaceae was merged with the New Caledonian Strasburgiaceae (APG III 2009).

Attribution

Fact Sheet prepared by P.J. de Lange (28 July 2005). Description based on Allan (1961), fresh material and herbarium specimens.

References and further reading

Allan, H.H. 1961: Flora of New Zealand. Vol. I. Wellington, Government Printer.

APG III 2009. An update of the Angiosperm Phylogeny Group classification of the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society 161: 105-121.

Gardner, R.O. 1997. Notes on the tawari Ixerba brexioides(Escalloniaceae). Auckland Botanical Society Journal, 52: 45-47.

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

This page last updated on 30 May 2015