Mullumbimby Couch

Mullumbimby Couch Description

A long-lived grass-like plant with long underground runners and upright flowering stems up to 40 cm tall. Its upright stems are three-angled in cross-section and only 0.5-1.5 mm thick. Its bright green leaves (1-3 mm wide) are hairless and sheath the stem at the base. Its pale green seed-heads (6-7 mm long) have three or four green leafy bracts at the base and contain numerous small flower spikelets. Its 'seeds' are yellow to reddish-brown in colour and topped with a small projection 1-1.5 mm long.

STEM AND LEAVES
Plants produce brownish or whitish coloured underground runners (i.e. rhizomes) which send up smooth, hairless (i.e. glabrous) stems that are upright (i.e. erect or ascending) in nature. These upright flowering stems are three-angled in cross-section (i.e. trigonous) and only 0.5-1.5 mm thick.

The bright green and shiny leaves (2.5-12.5 cm long and 1-3 mm wide) are hairless (i.e. glabrous) and have sheaths at the base. These leaves have entire margins and pointed tips (i.e. acute apices), and are clustered towards the bases of the flowering stems.

FLOWERS AND FRUITS
The seed-heads (i.e. inflorescences) are pale green, egg-shaped (i.e. ovoid) spikes. These flower spikes (6-7 mm long and 6-8 mm wide) have three or four green leafy bracts at the base and contain numerous densely packed flower spikelets. The flower spikelets consist of a bract (i.e. glume) 1.5-3 mm long and a single tiny flower (i.e. floret). Flowering occurs throughout the year.

The 'seeds' (i.e. nuts or achenes) are egg-shaped (i.e. ovoid), yellow to reddish-brown in colour, and topped with a small projection (i.e. beak) 1-1.5 mm long. They are often enclosed within papery whitish bracts (i.e. glumes).

REPRODUCTION AND DISPERSAL
This species reproduces by seed and vegetatively via its creeping stems (i.e. rhizomes).

Its seeds may be spread by water, animals, mowers or in contaminated soil. The creeping stems (i.e. rhizomes) spread laterally, enabling large colonies to be formed, and may also be spread in soil and dumped garden waste.

SIMILAR SPECIES
Mullumbimby couch (Cyperus brevifolius) is very similar to kyllinga weed (Cyperus sesquiflorus ) and reasonably similar to slender sedge (Cyperus gracilis ). These species can be distinguished by the following differences:

- Mullumbimby couch (Cyperus brevifolius) produces underground runners and has pale green coloured seed-heads. These small seed-heads (6-8 mm long) are very compact and egg-shaped (i.e. ovoid).

- kyllinga weed (Cyperus sesquiflorus ) only grows in tufts and has pale whitish-coloured seed-heads. These seed-heads (6-12 mm long) are very compact and usually have a larger central egg-shaped (i.e. ovoid) spike with two smaller spikes at the base.

Reference: https://weeds.brisbane.qld.gov.au/