Sebaea ovata
Common names
Sebaea
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Yellow
Detailed description
Short-lived 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
Three 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, is much larger than Sebaea and has blue-green, ovate or oblong-ovate, cordate leaves,
Distribution
Indigenous. In New Zealand, formerly known from both North and South Islands, and was last seen as two natural populations in the North Island, east and west of Whanganui, and two deliberately established populations on the remote Pouto Peninsula, near Dargaville and the Ashley/Rakahuri River mouth in Canterburyy. 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.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Threatened – Nationally Critical | Qualifiers: CD, SO
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 Whanganui. At both locations it is seriously at risk from weed encroachment and expansion of oioi (Apodasmia similis) swards, 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, attempts were made to maintain Sebaea by diligent management. This management involved weed spraying and the construction of fresh habitats using a bulldozer. This management proved unsuccessful.
Story in Trilepidea Issue 28 (March 2006)
Detailed taxonomy
Genus
Family
Synonyms
Exacum ovatum Labill., Gentiana ovata Dietr
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
November - January
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.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Other information
Cultivation
Not commericially available. Plants are held by two botanic gardens, one university and several specialist growers.
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.
SEBOVA
Chromosome number
2n = c.54
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Threatened – Nationally Critical | Qualifiers: CD, EF, SO
2012 | Threatened – Nationally Critical | Qualifiers: CD, DP, EF, SO
2009 | Threatened – Nationally Critical | Qualifiers: CD, SO, EF
2004 | Threatened – Nationally Critical
Referencing and citations
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.
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; updated 17 February 2025 by C.C. Ogle
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.