Juncus usitatus
Biostatus
Native
Category
Vascular
Structural class
Rushes & Allied Plants
Flower colours
Green, Yellow
Detailed description
Densely tufted, clump-forming, erect, slender, wiry, bright green to dark green perennial herb. Rhizome 2–3 mm diameter, horizontal. Flowering stems 0.5–1.2 m tall, 1–1.5 mm diameter, slender, finely ridged, not shining, light yellow-green, bright green to dark green, pith interrupted by numerous, irregular shaped lacunae or continuous. Leaves absent. Basal bracts short, closely appressed to the stem, lower bracts light grey, the upper bracts light brown, paler towards the apices. Inflorescence lateral, many-flowered, open and spreading, branchlets slender, curved, never clustered. Flowers 1.5–2.0 mm long, evenly spaced along inflorescence branchlets; tepals up to 2 mm long, initially pale green with very broad membranous margin, drying straw-yellow or pale brown. Stamens 3. Capsule 1.5–2 mm long, more or less equal, equal or slightly greater than tepals, trigonous-spherical to almost globose, shining, pale straw-coloured or light brown.
Similar taxa
The thin, wiry, usually bright-green stems, and widely and evenly spaced flower/capsules on long spreading branchlets are diagnostic for this species. It could only be confused with the introduced J. subsecundus N.A.Wakef. which differs by the blue-green stems and capsules which are consistently > 2 (rather than < 2) mm long.
Distribution
Indigenous. Kermadec, North, South, and Chatham Islands. Mainly northern but extending to about Canterbury. Also in Australia, Norfolk Island and New Caledonia.
Habitat
Coastal to lowland. Often on offshore islands. Usually in open ground or shrubland, more rarely under tall forest. Evidentally preferring seasonally dry clay soils or growing amongst rock. Preferring sunny situations. A common urban weed in Auckland City, where it often grows on exposures of basalt lava.
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 | Not Threatened | Qualifiers: SO
Detailed taxonomy
Family
Synonyms
Agathryon usitatum (L.A.S. Johnson) Záveská Drábková & Proćków
Taxonomic notes
Proćków et al. (2023) proposed a taxonomic segregation of Juncus into six genera based on molecular and morphological evidence. Whilst it has long been recognised that the current circumscription of Juncus includes morphologically divergent taxa—reflected in the recognition of numerous subgenera and sections—the consensus view of the NZPCN website taxonomy subcommittee, taking into consideration advice from Australian Juncus expert Dr Karen Wilson (NSW Herbarium) and others in Europe is that the generic segregations proposed need further consideration and testing. Accordingly, it has been decided to maintain the current broad circumscription of Juncus, but to include all new names as synonyms in factsheets. We thank, in particular, Dr Wilson for her helpful comments.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
October–April
Fruiting
October–September
Life cycle and dispersal
Mucilaginous seeds are dispersed by attachment, wind and water (Thorsen et al., 2009).
Propagation technique
Easy from fresh seed and by the division of whole plants. Can be invasive. Ideal for a sunny, seasonally damp clay soil.
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
juncus: From the Latin jungere ‘to tie or bind’, the stems of some species being used to make cord (Johnson and Smith)
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.
JUNUSI
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 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Johnson, A. T. and Smith, H. A. 1986. Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd, Buckenhill, UK.
Moore, L.B.; Edgar, E. 1970. Flora of New Zealand. Vol. II, Wellington, Government Printer.
Proćków, J., Záveská Drábková, L. 2023. A revision of the Juncaceae with delimitation of six new genera: nomenclatural changes in Juncus. Phytotaxa 622(1): 17–41.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285–309.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange (1 September 2006). Description based on Moore & Edgar (1970).
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): Juncus usitatus Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/juncus-usitatus/ (Date website was queried)