Callitriche chathamensis
Common names
Chatham Island starwort
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Detailed description
Stem and axillary scales present. Leaf bases connate. Lingulate leaves slightly wider toward apex, 1.0–1.4 mm long × 8.0–9.7 mm wide; expanded submerged or floating leaves ovate-elliptic 2.2–4.1 mm long × 0.8–2.5 mm wide, venation complex with frequent branches arising within and outside the secondary veins, secondary veins sometimes undulating, petiole 1.6–4.5 mm long; leaves of terrestrial plants unknown. Monoecious, flowers solitary, often alternating ♀ and ♂ along stem. Bracts lacking. Styles erect, 1.1–2.3 mm long. Filament erect, 4.5–6.8 mm long; anthers 0.5–0.6 mm long × 0.5–0.6 mm wide, quadrilocular; pollen yellow. Fruit not strumose, subsessile, wider than high, pale brown when mature, 0.6–0.9 mm long × 0.7–1.1 mm long wide, unwinged.
Similar taxa
Differs from C. petriei by its monoecious rather than dioecious habit, larger leaves (2.5-8 cf 1.1-5 mm), larger fruit (0.6-0.9 x 0.7-1.1 cf. 0.6-0.7 x 0.7-0.9 mm); by the pale or golden brown unwinged fruit which are wider than high, and the lack of floral bracts. As the species name implies this species is restricted to the Chatham Island archipelago.
Distribution
Endemic to the Chatham Islands
Habitat
Found on wet, peaty ground, commonly at the edges of streams and lakes, on bare peat and mud. Also in damp peaty turf on steep cliff faces, ledges and rubble near the sea.
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.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- 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 | At Risk – Naturally Uncommon | Qualifiers: DPR, DPS, DPT, IE, PF, RR
Threats
Not threatened and only listed because it is an island endemic which occupies a limited geographic area. It is abundant in suitable habitats on the two main Chatham Islands
Detailed taxonomy
Family
Plantaginaceae
Synonyms
Callitriche petriei subsp. chathamensis R.Mason
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
January - March
Fruiting
January - March
Propagation technique
Easy to grow from rooted pieces and rapidly becomes invasive. Not avery attractive plant for a garden but could be useful on the margin of the pond
Other information
Etymology
callitriche: From the Greek kalli ‘beautiful’ and thrix ‘hair’, referring to the beautiful stems
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.
CALCHA
Chromosome number
2n = 20
Previous conservation statuses
2017 | At Risk – Naturally Uncommon | Qualifiers: IE, RR, Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: IE, RR, Sp
2009 | At Risk – Naturally Uncommon | Qualifiers: IE
2004 | Range Restricted
Referencing and citations
References and further reading
Lansdown, R.V,. 2022: The genus Callitriche (Plantaginaceae, Callitricheae) in Australasia and Oceania. Phytotaxa 547: 243–284.
Attribution
Fact sheet prepared by P.J. de Lange for NZPCN (24 May 2022). Description from Lansdown (2022)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Callitriche chathamensis Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/callitriche-chathamensis/ (Date website was queried)