Vascular – Exotic
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.
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.
Scattered throughout both islands, locally abundant.
Wet areas such as the banks of rivers and streams, swamps, ditches.
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 to other Cyperus species, distinguished from the other species by the globular yellow-green flowerheads and basal leaves.
Summer to autumn
Summer to autumn
Seed dispersed by contaminated machinery.
North and South America
Reason for introduction
Unknown, possibly ornamental plant, seed or soil contaminant.
Can be controlled manually, mechanically or herbicidally depending on situation.
cyperus: From the ancient Greek name for sedge, kypeiros
eragrostis: From the Greek eros ‘love’ and agrostis ‘grass’
Prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
References and further reading
Healy, A.J.; Edgar, E. (1980). Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington. 220pp.
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.