Callitriche petriei subsp. chathamensis


Callitriche: From the Greek kalli 'beautiful' and thrix 'hair', referring to the beautiful stems
petriei: Named after Donald Petrei (1846 -1925), Otago botanist

Common Name(s)

Chatham Island starwort

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon
2004 - Range Restricted


2012 - IE, RR, Sp
2009 - IE


Callitriche petriei subsp. chathamensis R.Mason



Flora Category

Vascular - Native

NVS Species 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.

Structural Class

Dicotyledonous Herbs other than Composites




Endemic to the Chatham Islands


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.


Diminutive, monoecious, widely creeping perennial with weakly ascending to erect branches 30-100 mm long. Leaves 2.5-8 mm long, bright green to yellow green, spathulate to orbicular, the larger leaves often with short side veins arising from the midrib, and with two lateral veins. Flowers solitary, alternate on either side of stem, ebracteate. Fruit an more or less elliptic mericarp, laterally compressed, 0.6-0.9 x 0.7-1 mm, dull grey-brown or orange-yellow, lobes not rounded, keeled or winged.

Similar Taxa

Differs from C. petriei R.Mason subsp. 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), and restriction to the Chatham Island archipelago.


January - March


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


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

Chromosome No.

2n = 20

Endemic Taxon


Endemic Genus


Endemic Family


Where To Buy
Can be purchased from Oratia Native Plant Nurseries (info@oratianatives.co.nz)

This page last updated on 18 Jan 2010