Cyperus eragrostis
Common name
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 assessed
Brief 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.
Features
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’
Attribution
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.