Eleocharis pusilla
Biostatus
Native
Category
Vascular
Structural class
Sedges
Detailed description
Emergent or aquatic diminutive, sedge forming bright green (when exposed) or dark green to brown-green tufts. Rhizomes 1–3 mm diameter (usually very slender), pale brown. Culms densely tufted, 10–120 mm long, setaceous, < 0.5 mm diameter, bright green (when exposed), dark green to brown green with yellowish transverse bars when submerged; sheaths membranous, more or less hyaline, red-veined, uppermost sheaths colourless and inflated below the oblique orifice. Spikelet 2.5–3.0 × c. 1 mm, (1)–5-flowered, ovate, sharply acute. Glumes 1.5–2.0 mm long, ovate, obtuse. Hypogynous bristles mostly absent, rarely 2–3 present. Stamens 3. Style 3-fid. Nut c. 1.0 × 0.5 mm, narrowly obovoid, obscurely trigonous, almost white, each face with 3–4 thick, vertical ribs joined by fine transverse bars; the persistent style very small, much constricted at the base.
Similar taxa
Most likely to be confused with Eleocharis gracilis R.Br. from which it differs by the smaller spikelets (up to 3 mm long) and by the nut which has prominent vertical ribs and fine transverse bars. The culms of this species are often bright green, and distinctly tufted so as to resemble a small grass. In submerged plants the culms often have an obvious yellow transverse patterning on the otherwise dark green to brown-green coloured culms.
Distribution
Indigenous. In New Zealand known from North Island and South Island—often ucnommon over large parts of its range, and showing a decided preference for clean waterways free from pollution. Present in Australia.
Habitat
Usually found on the margins of and submerged within lakes, tarns and slow flowing rivers and streams. When submerged it often grows amongst drifts of quillworts (Isoetes spp.) and is rarely fertile. In emergent situations it is is easily overlooked because it has inconspicuous flowers and can be mistaken for a small tuft of grass.
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
Threats
Not Threatened—but not very common in the northern part of its range where it is clear, based on herbarium evidence that it has undergone a large decline. Still abundant in the deeper, cleaner and less polluted lake systems of the North Island. Common in the South Island.
Detailed taxonomy
Family
Synonyms
None—though New Zealand plants have at times been referred to the northern hemisphere Eleocharis acicularis (L.) Roem. et Schult.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–February
Fruiting
November–April
Life cycle and dispersal
Bristly nuts are dispersed by water and possibly wind and attachment (Thorsen et al., 2009).
Propagation technique
Can be tricky to establish. Does best as a submerged aquarium plant where it can be very attractive. Prefers semi-shade and regular immersion 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
Where To Buy
Not commercially available.
Etymology
eleocharis: Charm of the swamp
pusilla: Small
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.
ELEPUS
Chromosome number
2n = 30
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 | Qualifiers: SO
2009 | Data Deficient | Qualifiers: SO
2004 | Not Threatened
Regional conservation statuses
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 “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Otago: 2024 | Regionally Not Threatened
Referencing and citations
References and further reading
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
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.
Attribution
Description adapted from Moore and 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.