New Zealand watercress, Matangaoa
Arabis gigantea Hook.f., Cardamine divaricata Hook.f., C. stylosa DC, Nasturtium stylosum (DC) Schulz, Rorippa stylosa (DC.) Allan, R. gigantea (Hook.f.) Garn.-Jones
Vascular – Native
Dicotyledonous Herbs other than Composites
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.
2n = 48
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Threatened – Nationally Vulnerable | Qualifiers: EF
Previous conservation statuses
2009 | Threatened – Nationally Vulnerable | Qualifiers: EF
2004 | Threatened – Nationally Endangered
Endemic. Known from the Kermadec, Three Kings, North, South and Chatham Islands. It has not been seen on the Kermadecs for over 100 years but is still present on the Three Kings, Poor Knights and other Hauraki Gulf Islands. In the North Island it has been recorded recently from Kawhia, Hicks Bay and the Rotorua Lakes district. In the South Island it is known from and in the vicinity of the Abel Tasman National Park. On the Chatham Islands it has been collected once in 1985 and not reliably reported since.
A species of recently disturbed ground. Usually found in or near clearings, on recent slips or on track margins. Often on lake and river margins. Plants may also grow within active petrel colonies, often around burrow entrances. This species seems to do best in dappled light, and is often found in forested habitats. It has also been found in pine plantations.
Annual to perennial herb (depending on local growing conditions), 0.3-2 m tall, arising from stout taproot. Basal stem one (or more), erect to decumbent, glabrescent, woody, purple red when mature, somewhat angled. Leaves green, yellow-green, dark green or purple-green, margins sinuate, dentate to deeply toothed. Basal leaves petiolate, petiole broadly winged, grading into deflexed amplexicaul leaf lobes; lamina 30-160 x 20-80 mm, pinnatifid. Mid cauline leaves similar but smaller, upper cauline leaves much smaller, linear-lanceolate, simple, basally cuneately narrowed or amplexicaul. Inflorescence a complex, heavily branched raceme. Racemes 50-200 mm long. Pedicels 5-20 mm long at flowering, erecto-patent, spreading to deflexed at fruiting. Sepals 2-3 mm long. Petals white 2-3 mm long. Fruit a dark green to purple-green silique, 10-40 x 1-2 mm, spreading, linear, more or less terete, shallowly grooved along suture. Style remnant c.2 mm long. Seeds orange to red-brown, c.1 mm diam., extremely sticky when fresh.
Spring (can flower from October to February)
Summer (can fruit from October to May)
Easy from fresh seed. A very fast growing and weedy species which can become invasive.
Weed competition is a major threat. Trampling, vegetation succession and vegetation clearance will also threatened populations. Plants are prone to drought. Browsing animals (possums, rodents, stock and feral pigs) and exotic insect pests (particularly cabbage white butterfly) are also significant threats.
rorippa: A latinized form of Rorippen, a Saxon vernacular name used by Euricius Cordus
divaricata: Spreading or branching at wide angles
Where To Buy
Occasionally available from specialist native plant nurseries.
The young leaves, stems, flowers, seed capsules, are delicately and pleasantly flavoured, and together with Cooks scurvy grass (Lepidium oleraceum Sparrman), celery (Apium prostratum subsp. prostratum var. filiforme (A.Rich) Kirk, and native spinach (Tetragonia tetragonoides (Pall.) Kuntze) make a great indigenous summer salad.
Fact Sheet Prepared by P.J. de Lange (1 November 2009). Description by P.J. de Lange subsequently published in de Lange et al (2010).
References and further reading
de Lange, P.J.; Heenan, P.B.; Norton, D.A.; Rolfe, J.R.; Sawyer, J.W.D. 2010: Threatened Plants of New Zealand. Canterbury University Press, Christchurch.
Please cite as: de Lange, P.J. (Year at time of access): Rorippa divaricata Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/rorippa-divaricata/ (Date website was queried)