Myosurus minimus subsp. novae-zelandiae
Common names
New Zealand mousetail
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Green, Yellow
Detailed description
Spring to summer-green annual, forming tufts 10–80mm tall. Leaves 5–20, 10–35 × 1–2.5 mm, basal, fleshy to succulent, exstipulate, linear to linear-spathulate, obtuse, margins entire, bright to dark green, yellow-green, red-green or red. Inflorescences scapigerous, scapes 1–8, 1-flowered, 10–80 mm tall (including receptacle), erect to spreading, glabrous, fleshy, filiform, bright to dark green, yellow-green, red-green or red. Flowers greenish–yellow, apetalous. Sepals 5, minute, 0.5–0.8 mm long, 3-nerved, ovate to oblanceolate, green to greenish-yellow or green-red, Stamens 5, filaments 0.3–0.5mm long, greenish-white. Receptacle 3–15 mm long, elongating in fruit, oblong to oblong-linear, bearing numerous carpels. Styles 0.4–0.5 mm long. Achenes 20–50 (or more), 0.9–1.6 mm long, boat-shaped, body oblong to narrow-oblong, broader at apex, surface glabrous, dull, pale brown, yellow-brown to dark brown, beak 0.4 mm long. Seed 0.55–0.90mm, narrowly elliptic to elliptic, surface finely rugulose, semi-glossy, brown to dark brown.
Similar taxa
May be confused with Limosella australis R.Br. from which it differs by its greenish-yellow rather than white, lilac to pink flowers and by the conspicuous, elongated receptacles which bear numerous carpels (rather than the solitary subglobose capsules produced by L. australis). It may also be confused with Plantago coronopus L., which differs from mousetail by its dark green to brown-green, usualy 1–4 lobed linear leaves, sparsely hairy leaves, and many flowered spikes.
Distribution
Endemic. New Zealand: North Island (formerly reported from the Hawkeʻs Bay to Cape Palliser and Island Bay near Wellington, places where it is now believed extinct), South Island (known only from the eastern side, from Marlborough south to Lake Manapouri).
Habitat
Lowland to upland. Damp and slightly salty depressions in pastures and short tussock grassland, on the margins of tarn and kettle holes, and in damp dune hollows, gravel flats and alluvium.
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 | At Risk – Declining | Qualifiers: Sp, DPS, EF, RR
Threats
Mousetail is probably a biologically sparse entity. However, virtually all of its known habitats are now being invaded by faster growing, taller or turf forming, perennial weeds such as Plantago coronopus. These weed invasions appear to be accelerated by changes in the surrounding hydrology, caused in turn, by changes in land use. In particular, the conversion of upland mixed sheep/cattle and sheep farms to dairy farms, especially within Canterbury and Otago, has increased the need for ground water. Canalisation and the widespread use of bore water is now visibly reducing the number of ephemeral wetlands, kettle holes and tarns once frequented by mousetail and other marginal turf plants.
Detailed taxonomy
Genus
Family
Synonyms
Myosurus novae-zelandiae W.R.B.Oliv., M. minimus L. subsp. minimus
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
August–November–(January)
Fruiting
September–February
Propagation technique
A strict annual, easily grown from fresh seed. It does best in a small pot, partially submerged in water.
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
Etymology
minimus: Smallest (rather a misnomer)
novae-zelandiae: Of New Zealand
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.
MYOMSN
Chromosome number
2n = 16
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, EF, RR, Sp
2012 | Threatened – Nationally Endangered | Qualifiers: DP, EF, RR, Sp
2009 | Threatened – Nationally Critical | Qualifiers: EF, Sp
2004 | Threatened – Nationally Endangered
Regional conservation statuses
Otago: 2025 | Regionally Threatened – Regionally Endangered | Qualifiers: EF, NR, NStr, PF, RR
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 “Conservation Status of Indigenous Vascular Plants in Otago, 2025” Jarvie S et al. (2025) report.
Referencing and citations
References and further reading
de Lange PJ, Heenan PB, Norton DA, Rolfe JR, Sawyer JWD. 2010. Threatened Plants of New Zealand. Canterbury University Press, Christchurch. 471 p.
Ogle CC. 1985. Mouse-tail Myosurus novae-zelandiae a declining species? Wellington Botanical Society Bulletin 42: 57–61.
Attribution
Fact Sheet prepared for the NZPCN by P.J. de Lange 14 April 2006. Description by P.J. de Lange and subsequently published in de Lange et al. (2010).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Myosurus minimus subsp. novae-zelandiae Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/myosurus-minimus-subsp-novae-zelandiae/ (Date website was queried)