Tetrachondra hamiltonii
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Green, White
Detailed description
Creeping perennial herb rooting at nodes forming diffuse to dense turf-like patches. Stems fleshy, distinctly angled, square in cross-section, dark striped. Leaves opposite, 2 × 2 mm, broadly ovate to obovate-oblong, bright green or mottled with red, fleshy, sparsely covered with indistinct circular oil glands, glabrescent (leaf margins often faintly ciliolate), shortly petiolate to sessile, bases decurrent with stem. Flowers soliatry, off-white to greenish-white. Calyx lobes minute, ovate-triangular. Corolla lobes 4, obovate-oblong, pubescent. Stamens and styles 4. Fruit 4 brown setulose nutlets, broadly elliptic or obovate, (1)–1.1–1.4–(1.5) mm.
Similar taxa
Without fruits this diminutive creeping herb could be easily confused with a diverse range of other unrelated turf-forming herbs, e.g., Nertera spp., Crassula spp., Galium spp. However, the distinctive 4-fruited setulose nutlets immediately distinguish it from these and other potential look alikes.
Distribution
Endemic. New Zealand: North Island (NW corner of the Ruahine Ranges), South Island (localised but widespread, with the main centre of distribution in Otago, western Southland, Fiordland), Stewart Island/Rakiura.
Habitat
A species of open, compact turf communities such as those developed along lake and tarn margins, flushes and seepages. Occasionally found in suitably open sites within forest.
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 Vulnerable | Qualifiers: Sp, DPR, DPT
Threats
A naturally uncommon species of open damp turf, seepages, and the marginal turf communities of lakes and tarns. Sometimes in open scrub or damp grassland. Indications are that in parts of its range it is declining, possibly as a consequence of taller, faster growing weeds spreading into the habitats it requires.
Detailed taxonomy
Family
Synonyms
Tillaea hamiltonii Kirk nom. nud.
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
Flowers may be found throughout the year
Fruiting
Fruits may be found throughout the year.
Propagation technique
Easily grown from the division of whole 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 commercially available but plants are held by several Botanic Gardens and specialist growers. It is very easily grown but is not particularly attractive.
Etymology
hamiltonii: Named after W. S. Hamilton (of Southland)
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.
TETHAM
Chromosome number
2n = 72
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 Vulnerable | Qualifiers: DP, Sp
2012 | Data Deficient | Qualifiers: Sp
2009 | At Risk – Declining | Qualifiers: DP, Sp
2004 | Serious Decline
Regional conservation statuses
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Otago: 2024 | Threatened – Regionally Endangered | Qualifiers: DPT, NStr, PD, RR
Referencing and citations
References and further reading
Allan HH. 1961. Flora of New Zealand, Volume I. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. Government Printer, Wellington, NZ. 1085 p.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 1 August 2003. Description based on Allan (1961).
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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Tetrachondra hamiltonii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/tetrachondra-hamiltonii/ (Date website was queried)