Cyperus sanguinolentus


Cyperus: From the ancient Greek name for sedge, kypeiros

Common Name(s)

Louisiana flatsedge


Cyperus sanguinolentus Vahl



Brief 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.

Flora Category

Vascular - Exotic

Structural Class



Pycreus sanguinolentus (Vahl) Nees


Restricted to Northland and Auckland.


Wet pasture, margins of water bodies and drains.


Tufted annual. Stems to 40 cm high, 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.


Summer to autumn

Flower Colours



Summer to autumn

Year Naturalised



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.


Factsheet 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.

Johnson PN, Brooke PA (1989).  Wetland plants in New Zealand.   DSIR Field Guide, DSIR Publishing, Wellington. 319pp.

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

This page last updated on 14 Mar 2016