Juncus pusillus
Common names
dwarf rush
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Rushes & Allied Plants
Flower colours
Green, Red/Pink
Detailed description
Diminutive, delicate, red-brown to dark brown, perennial forming widely creeping tufted patches arising from an ascending rhizome 0.5 mm diameter. Stems 1–30 × 0.2–0.3 mm, leafy, creeping and rooting below, erect above. Leaves basal and cauline, usually > stems, up to 0.2 mm wide, filiform, striated, terete, septate; sheath membranous with two obtuse auricles. Inflorescence terminal, usually solitary flowered, rarely with 2–3 sessile flowers or comprised of two slender branches terminated by 2–3 flowers; subtending bract > inflorescence. Flowers 1.5–2.0 mm long, tepals equal, initially pale green, maturing reddish. Stamens 6, equal in length or > tepals. Capsule pale brown, slightly > tepals, narrowly ovoid, distinctly mucronate.
Similar taxa
Most likely to be confused with J. scheuchzerioides Gaud. (with which it grows on the Auckland Islands) and J. novae-zelandiae Hook.f. From J. scheuchzerioides it differs by the terete rather than compressed red brown to brown rather than pale green, red-green to bright green leaves which are < rather than > 0.5 mm wide. Further it has flowers which are 1.5–3 rather than 4 mm long. From J. novae-zelandiae it differs by the light brown rather than lustrous black tipped mature capsules and stems which are less than the length of the leaves at maturity.
Distribution
Endemic. new Zealand: North Island (south of Bay of Plenty), South Island.
Habitat
Open, swampy ground, in cushion bogs and alongside tarn, lake and river margins. Coastal to alpine. Often associated with Juncus novae-zelandiae Hook.f.
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: Sp, DPS, DPT, RR, SO
Detailed taxonomy
Family
Juncaceae
Synonyms
Juncus capillaceus Hook.f., Verojuncus pusillus (Buchenau) 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
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
October–January
Fruiting
December–May
Life cycle and dispersal
Mucilaginous seeds are dispersed by attachment, wind and water (Thorsen et al., 2009).
Propagation technique
Easy from fresh seed and the division of whole plants. Very small, and best kept in a 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]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely 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)
pusillus: Insignificant or weak
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.
JUNPUS
Previous conservation statuses
2017 | At Risk – Naturally Uncommon | Qualifiers: DP, SO, Sp
2012 | Not Threatened | Qualifiers: SO, Sp
2009 | At Risk – Naturally Uncommon
2004 | Not Threatened
Referencing and citations
References and further reading
Johnson AT, Smith HA. 1986. Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd, Buckenhill, UK.
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
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. https://doi.org/10.11646/phytotaxa.622.1.2.
Thorsen MJ, Dickinson KJM, Seddon PJ. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285–309. https://doi.org/10.1016/j.ppees.2009.06.001.
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 pusillus Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/juncus-pusillus/ (Date website was queried)