Species

Sebaea ovata

Common Name(s)

Sebaea

Current Conservation Status

2012 - Threatened - Nationally Critical

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 - Threatened - Nationally Critical
2004 - Threatened - Nationally Critical

Qualifiers

2012 - CD, DP, EF, SO
2009 - CD, SO, EF

Authority

Sebaea ovata (Labill.) R.Br.

Family

Gentianaceae

Flora Category

Vascular - Native

NVS Species Code

SEBOVA

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 Herbs other than Composites

Synonyms

Exacum ovatum Labill., Gentiana ovata Dietr

Distribution

Indigenous. In New Zealand formerly known from both North and South Islands, now confined to two natural populations in the North Island near Wanganui, and two deliberately established populations on the remote Pouto Peninsula, near Dargaville. Present also in Australia (South Australia, Victoria, New South Wales and Tasmania) where it is very common.

Habitat

Coastal. Associated with damp, sparsely-vegetated dune slacks, depressions, and associated sand plains. In Australia more widespread, ranging from the coast inland to montane forest, often but not exclusively in seasonally damp ground.

Features

Annual, sparingly branched, erect herb, 50-300 mm tall. Stems 4-angled, hairless, pale yellow-green. Leaves, sessile , in opposite pairs, 6.5 x 15 x 5-10 mm, fleshy, pale green to almost blue-green, ovate to broadl-ovate or suborbicular, apex obtuse to subacute, well spaced along stem; midrib prominent, with one conspicuous longitudinal vein either side. Inflorescence a mainly terminal cyme, with a few solitary flowers borne within the subtending leaf axils. Flowers 6.5 mm long, scarcely opening; calyx-lobes 5, narrowly ovate-lanceolate, acute with rigid narrowly winged keel. Corolla tube 4 mm, straight, pale yellow, corolla lobes 5, 3 mm long, pale yellow, linear-lanceolate to lanceolate, often twisted. Ovary 2-locular. Capsules ovoid-ellipsoid, 5 mm long. Seeds fine, dust-like.

Similar Taxa

Two introduced weeds, centuary (Centaurium erythraea Rafn. and C. tenuiflorum (Hoffm. et Link) Fritsch) and Blackstonia perfoliata (L.) Hudson occupy the same habitat, and are superfically similar. Centuary can be distinguished by its pink to deep rose flowers, whose anthers spirally twist after anthesis, and by the 1-locular rather than 2-locular ovary. Blackstonia perfoliata is most common in Northland and is much larger than Sebaea and has blue-green, ovate or oblong-ovate, cordate leaves,

Flowering

November - January

Flower Colours

Yellow

Fruiting

December - February

Propagation Technique

Can be grown from fresh seed. Not especially easy to grow, requiring specialist knowledge to successfully germinate and maintain plants.

Threats

Though formerly ranging from near Hokianga Harbour in the North Island to Lake Ellesmere in the South Island, by the 1980s S. ovata was known from only two sites near Wanganui. At both locations it is seriously at risk from weed encroachment, caused in part by changing water levels in the adjacent dune systems but also due to the release of rabbit calcivirus, which having locally eliminated rabbits, facilitated the spread of weeds normally suppressed by these animals into suitable Sebaea habitat. At both locations Sebaea is being maintained only by diligent management. this management has involved weed spraying and the construction of fresh habitats using a bull dozer.

Chromosome No.

2n = c.54

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

Where To Buy

Not commericially available. Plants are held by two botanic gardens, one university and several specialist growers.

Attribution

Fact Sheet prepared by P.J. de Lange 20 October 2003. Description based on Allan (1961) supplemented with observations made from fresh and/or dried herbarium specimens

References and further reading

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

Growth and habitat of Sebaea ovata (Gentianaceae) in New Zealand and Australia by P.D. Champion, D.E Hofstra, M.E. Auger, and C.E.C. Gemmill.

Ogle, C.C. 1989. Sebaea ovata and its habitat near Wanganui. Wellington Botanical Society Bulletin, 45: 92-99

This page last updated on 17 Apr 2014