Cyperus sanguinolentus
Common names
Louisiana flatsedge
Biostatus
Exotic
Category
Vascular
Structural class
Sedges
Simplified description
Tufted yellow-green leafy sedge, with triangular stems up to 40 cm tall, with 1 or occasionally 2 or 3 distinctively green and purple red striped flowerheads, each made up of flattened flower spikes, with two to three grass-like leaves immediately under this, at the end of flower stalk.
Flower colours
Green, Purple
Detailed description
Tufted annual. Stems to 40 cm tall, very slender in small plants but more rigid in larger ones, 3-angled, very leafy at base. Leaves < stems, to 2.5 mm wide, margins smooth except near tip. Involucral bracts 2–3, very widely spreading, unequal, at least the lowest >, to very much > inflorescence. Inflorescence a single head or small umbel with few very short rays. Spikelets in ovoid dark clusters, oblong or oblong-lanceolate, 4–8 × 2 mm, much compressed. Glumes not closely imbricate, ± 2 mm long, ovate, obtuse, with broad green keel and dark red-purple patch at tip and purple band inside the green margin. Stamens 3 or 2. Style-branches 2. Nut ± ½ length of glume, orbicular-obovoid, biconvex, black.
Similar taxa
Most similar to the native Schoenus apogon, but the dark purple lined green flattened spikelets and triangular stems distinguish P. sanguinolentus from this species.
Distribution
Restricted to Northland and Auckland.
Habitat
Wet pasture, margins of water bodies and drains.
Conservation status
Not applicable
Detailed taxonomy
Family
Cyperaceae
Synonyms
Pycreus sanguinolentus (Vahl) Nees
Ecology
Flowering
Summer to autumn
Fruiting
Summer to autumn
Year naturalised
1944
Origin
North Africa, Asia and Australia
Reason for introduction
Unknown, possibly ornamental plant, seed or soil contaminant.
Control techniques
Not controlled in New Zealand.
Life cycle and dispersal
Seed dispersed by contaminated machinery.
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).
Other information
Etymology
cyperus: From the ancient Greek name for sedge, kypeiros
Referencing and citations
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.
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.