bunchy sedge

Cyperus polystachyos
Grass
Basal
Simple
Brown
Green

A tufted, long-lived, grass-like plant with upright flowering stems growing up to 80 cm tall. Its rigid stems (1-3 mm thick) are hairless and triangular in cross-section its very narrow leaves (1-4 mm wide) are grass-like in appearance and tufted at the base of the plant. Its seed-head is an irregular cluster of brownish-coloured spikes subtended by three to six green leafy bracts this seed-head may be unbranched or with several short branches up to 6 cm long its elongated flower spikelets (5-15 mm long and about 2 mm wide) are borne in dense clusters.

Family 
Cyperus polystachyos
Deciduous 
Flowering time 
Late Spring-Summer
Common names 
Also known as: Coast flatsedge, Many spiked sedge, Texas sedge,
Origin 
Native to Africa, southern and eastern Asia, Australia, North America, Central America, the Caribbean and South America. Native to large parts of northern and eastern Australia. It is widespread in south-eastern Queensland, but is far more common on coast
Known distribution 

A weed of crops, drainage channels, pastures, disturbed sites, waste areas, roadside ditches, footpaths and gardens. It grows naturally in damp habitats (i.e. swamps and wetlands) and occasionally also on drier sandy soils.

Habitat 

A weed of crops, drainage channels, pastures, disturbed sites, waste areas, roadside ditches, footpaths and gardens. It grows naturally in damp habitats (i.e. swamps and wetlands) and occasionally also on drier sandy soils.

Habit 

A tufted, long-lived (i.e. perennial), grass-like plant with upright (i.e. erect) flowering stems growing up to 80 cm tall.

Stem and leaves 

The stems (1-3 mm thick) are rigid and triangular in cross-section (i.e. trigonous). They are also smooth and hairless (i.e. glabrous). The very narrow (i.e. linear) leaves are grass-like in appearance and hairless (i.e. glabrous). These leaves (1-4 mm wide) are clustered at the base of the plant. They have entire margins and pointed tips (i.e. acute apices).

Flowers and fruits 

The seed-head (i.e. inflorescence) is an irregular cluster of brownish coloured spikessubtended by three to six green leafy bracts. This seed-head may be an unbranched stalkless cluster or have several short branches up to 6 cm long. The flower spikelets are elongated and flattened (5-15 mm long and about 2 mm wide) with a pointed tip (i.e. acute apex) and contain up to 30 tiny flowers (i.e. florets). These flower spikelets are borne in densely packed (i.e. congested) clusters and turn from greenish to yellowish-brown and then to greyish-brown in colour as they mature. The 'seeds' (i.e. nuts or achenes) are brown to black in colour, oblong (i.e. obloid) in shape (about 1 mm long), and have a small projection at the top (i.e. they are apiculate).

Reproduction and dispersal 

This species reproduces mainly by seed. These seeds may be spread by water or in mud attached to animals and vehicles.

Impact and control methods 
Foliar spray
or
Slashing and mowing

Bunchy sedge (Cyperus polystachyos) is similar to rice flat-sedge (Cyperus iria), drain flat-sedge (Cyperus eragrostis) and dirty Dora (Cyperus difformis). These species can be distinguished by the following differences: bunchy sedge (Cyperus polystachyos) has unbranched or shortly branched seed-heads that turn brownish or yellowish-brown as they mature. The pointed flower spikelets are densely packed in a single stalkless cluster or in irregularly shaped clusters at the tips of the short branches rice flat-sedge (Cyperus iria) has branched seed-heads that turn golden-yellow in colour as they mature. The flower spikelets are loosely arranged in elongated clusters at the tips of the branches drain flat-sedge (Cyperus eragrostis) has branched seed-heads that turn golden-yellow or yellowish-brown as they mature. The flower spikelets are densely packed in rounded clusters at the tips of the branches dirty Dora (Cyperus difformis) has branched seed-heads that turn reddish brown or dark brown as they mature. The flower spikelets are densely packed in rounded clusters at the tips of the branches.

Native/Exotic 
Native
Notifiable 
No
Council declaration 
SIL