Cyperus eragrostis
Environmental Weed (2024)
Common names
umbrella sedge
Family
Cyperaceae
Flora category
Vascular – Exotic
Structural class
Sedges
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.
CYPERA
Conservation status
Not applicable
Simplified description
Tufted leafy sedge, with triangular stems up to 90 cm tall, leaves arranged in threes, with a group of 5 to 7 green round flowerheads, each made up of broad flattened flower spikes, with 5 to 8 long grass-like leaves immediately under this, at the end of flower stalk.
Distribution
Scattered throughout both islands, locally abundant.
Habitat
Wet areas such as the banks of rivers and streams, swamps, ditches.
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).
Detailed description
Rhizome short, thick, woody. Stems 25–90 cm high, stout, obtusely trigonous, smooth, leafy and ± thickened at base. Leaves usually < stems, 4–8 mm wide, flat, margins finely serrate; sheaths dark purple-brown. Involucral bracts 5–8, leaf like, unequal, often very much > inflorescence. Inflorescence a compound umbel, rather variable in size; rays 5–7–(9), of unequal length, each with a dense pale green to yellow-green globose or hemispherical spike at tip, 1–2 cm diam. Spikelets many, densely crowded, much compressed, ± 5–12 × 3 mm, ovoid-oblong, subacute. Glumes many, ± 2 mm long, densely imbricate, ovate, membranous, cells very distinct, whitish-cream to light brown, 1-distinct lateral nerve on each side, keel green, tip slightly recurved. Stamen 1. Style-branches 3. Nut ± ½ length of glume, trigonous, obovoid brown (Healy and Edgar, 1980).
Similar taxa
Similar to other Cyperus species, distinguished from the other species by the globular yellow-green flowerheads and basal leaves.
Flowering
Summer to autumn
Flower colours
Green, Yellow
Fruiting
Summer to autumn
Life cycle
Seed dispersed by contaminated machinery.
Year naturalised
1871
Origin
North and South America
Reason for introduction
Unknown, possibly ornamental plant, seed or soil contaminant.
Control techniques
Can be controlled manually, mechanically or herbicidally depending on situation.
Etymology
cyperus: From the ancient Greek name for sedge, kypeiros
eragrostis: From the Greek eros ‘love’ and agrostis ‘grass’
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
Attribution
Prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
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.
References and further reading
Champion P. et al. 2020. Freshwater Invasive Species of New Zealand 2020. NIWA publication. https://docs.niwa.co.nz/library/public/FreInSpec.pdf
Healy AJ, Edgar E. 1980. Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington, NZ. 220 p.
Johnson PN, Brooke PA. 1989. Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington, NZ. 319 p.