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Cyperus brevifolius (Rottb.) Hassk. 1844
pronounced: sy-PEE-rus brev-ih-FOH-lee-uss
(Cyperaceae – the papyrus family)
common name: Mullumbimby Couch
Cyperus is from the Greek κυπειρος (kypeiros), a sweet-smelling marsh plant; brevifolius is from the Latin, brevis, short, and folium, a leaf.
This is a perennial grasslike plant with long creeping pink to brown underground rhizomes, with roots under every stem, and upright flowering stems 5 – 40 cm tall. The maximum heights are achieved only in very moist places. It is a common weed of gardens and lawns, disturbed sites, waste areas and wetter pastures. It is regarded as an environmental invasive weed in many parts of Australia. Its origin is unknown, but some botanists believe that it came from tropical Asia and the warmer temperate regions of China and Japan. It is very widely naturalized in the coastal and sub-coastal regions of Australia, especially in the northern and eastern parts of the country. It is also naturalized on Lord Howe Island and Norfolk Island, and possibly in South Australia.
The leaves are a shiny green in colour, 1 – 2 mm in width, 2.5 – 12.5 cm long, and channeled, with sheaths at the base. They have acute apices and entire margins, and are clustered at the base of the flowering stems. These stems, that normally bear only one inflorescence, are triangular in cross-section, 0.5 – 1.5 mm thick, and smooth.
The inflorescences are pale green and ovoid or subglobose in shape, about 6 – 8 mm across, with up to about 100 tiny flowers on each head. They protrude above the plant. They have 3 or 4 green leafy bracts at the base, and the flower spikelets are densely packed. The flower spikelets consist of a glume 1.5 – 3 mm long and a single floret with 1 or 2 (rarely 3) stamens, and a bifid style. Flowering occurs throughout the year.
The fruits are tiny nuts with both surfaces convex. They are pear-shaped to elliptic, yellow-brown in colour, and topped with a small beak 1 – 1.5 mm long. The testa is very smooth. They are often enclosed within papery whitish bracts.
Reproduction is by both seed and vegetatively, i.e. by the creeping rhizomes.
This plant spreads quite easily under quite dense vegetation, and is resistant to herbicides. The only effective way of getting rid of it is land removal, in order to remove all of the rhizomes.
Photographed in Picnic Bay, March2019
Page last updated 13th April 2019