Carex scoparia
Common names
broom 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.
CARSCO
Conservation status
Not applicable
Simplified description
Very dense green grass-like tufts up to 1 m tall, leaves conspicuously arranged in three planes, with slightly taller flower stem bearing pale green or yellow-brown oval heads near the tip.
Distribution
Scattered throughout the North island, absent from most eastern areas.
Habitat
Swamps and lake margins.
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
Very dense leafy tufts up to 90 cm high. Stems slender, sharply 3-angled, scabrid on margins below inflorescence. Leaves < stems, 2–3 mm wide, ± flat. Inflorescence 2–6 cm long, of 4–12 very clearly defined sessile spikes aggregated into an oblong or linear-oblong head; one or two lower spikes with small inconspicuous setaceous bracts < inflorescence. Spikes androgynous, male flowers at base, oblong or ovoid-oblong, tapering or rounded at apex. Glumes < utricles, lanceolate, acute, narrower than utricles at tip, light brown or white-hyaline, midrib green. Utricles ± 4 × 1–1.5 mm, lanceolate to narrow ovate-lanceolate, flat, faintly nerved on each side, greenish to brownish, ± narrowly winged throughout, minutely scabrid on margins of upper half, tapering to a beak ± 1 mm long. Stigmas 2. Nut ovoid-oblong.
Similar taxa
Two other Carex spp. have oval spikes (C. leporina and C. longii). C. scoparia is more robust than the other species and usually has more spikes per culm (see comparison with C. ovalis in photo).
Flowering
Late spring to early summer
Flower colours
Brown, Green
Fruiting
Summer to autumn
Life cycle
Seed dispersed by contaminated machinery or waterfowl.
Year naturalised
1948
Origin
North America
Reason for introduction
Unknown, seed or soil contaminant
Control techniques
Not controlled in New Zealand.
Etymology
carex: Latin name for a species of sedge, now applied to the whole group.
Attribution
Factsheet 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.