Eleocharis acuta
Common names
sharp spike sedge
Biostatus
Native
Category
Vascular
Structural class
Sedges
Detailed description
Terrestrial or semi-aquatic sedge forming yellow-green to green somewhat distinct, crowded tufts. Rhizomes lignaceous, widely creeping, 1–2 mm diameter. Culms more or less crowded in distant tufts, 15–900 × 0.5–2.5 mm, more or less erect, terete, distinctly striated; lower sheath dark red to maroon with an oblique orifice, upper sheath paler, closely appressed to culm, orifice usually truncate or rarely slightly oblique, with dark thickened edge and distinct mucro at back. Spikelet 5–25 × 2–5 mm, cylindrical, acute at apex. Glumes numerous, basal 2 sterile, shorter, broader and paler than rest, upper glumes ovate-lanceolate with hyaline apices. Hypogynous bristles 6–8, ≥ nut. Stamens 3. Style 3-fid. Nut 1.5 × 1.0 mm, obovoid, biconvex or plano-convex, pale brown, smooth or faintly reticulate; the small persistent style-base triangular, compressed, white or very pale brown.
Similar taxa
Distinguished from the somewhat similar Eleocharis pusilla R.Br. and E. gracilis R.Br. by the much larger size, and by the usually truncate (only rarely slightly oblique), distinctly mucronate uppermost leaf-sheath which has a thickened orifice. In the other two species the uppermost leaf-sheath has a consistently oblique orifice and is without a mucro.
Distribution
Indigenous. In New Zealand found on the Kermadec Islands, North Island, South Island, Stewart Island/Rakiura and Chatham Islands. Also in Australia and on Norfolk Island.
Habitat
Coastal to montane. Common in open to partially shaded permanently damp ground. Usually in swamps, and on stream, river, pond, and lake margins. Sometimes present in seepages within pasture.
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 | Not Threatened | Qualifiers: SO
Detailed taxonomy
Family
Cyperaceae
Synonyms
Eleocharis acuta R.Br. var. platylepis Hook.f.; Eleocharis acuta R.Br. var. tenuis Carse
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–January
Fruiting
October–May
Life cycle
Bristly nuts are dispersed by water and possibly wind and attachment (Thorsen et al., 2009).
Propagation technique
Easy from fresh seed and the division of whole plants. Does best partially submerged but will also grow in damp soil. Needs full sun to flower.
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
Cultivation
Occasionally sold by specialist native plant nurseries.
Etymology
eleocharis: Charm of the swamp
acuta: From the Latin acutatus ‘sharp’, refers to something sharpened or with an acute angle
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.
ELEACU
Chromosome number
2n = 20
Previous conservation statuses
2017 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | 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.