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Cyperus involucratus Rottb. 1772
pronounced: sy-PEE-rus in-voll-yoo-KRAH-tuss
(Cyperaceae – the sedge family)
common name: Umbrella Sedge
Cyperus is from the Greek κυπειρος (kypeiros), a sweet-smelling marsh plant; involucratus is from the Latin involucrum, a wrapper, covering, or case. The genus is a large one of about 600 species of annual and perennial grass-like herbs occurring throughout the world except for very cold regions. There are about 130 species native to Australia.
This is a close cousin of the famous Egyptian papyrus plant Cyperus papyrus, which it resembles. The Egyptians made paper from that plant, and many of our earliest manuscripts are written on papyrus. Cyperus involucratus is not, however, native to Australia. It is believed to be a native to moist boggy areas, and lake and river margins, on the island of Madagascar. It has naturalized throughout much of Africa, and in many tropical regions. On Magnetic Island it is found growing in many of the dry creek beds.
The clumps are composed of slender stems with triangular cross-section that arise from a network of woody rhizomes and grow to a height of 60–180 cm. The small basal leaves are barely noticeable, as they are reduced to sheaths at the bottom of the stems. At the stem tips there are usually 10–15 leaf-like bracts 50–40 cm long and a little over 1 cm wide, radially arranged like the spokes of a wheel. Clusters of small greenish flowers grow from the centre of the disk. The flowers are followed by small fruits that mature to dark brown. Once established, this plant is very persistent.
Gardeners use the umbrella sedge as an accent plant along the banks of lakes and ponds. In fish ponds, it is often planted in containers to restrict its spread. In bright sun, the clumps are compact and the stems closely packed. Under shady conditions the clumps will grow higher, and be composed of fewer stems and larger leaves, giving a more graceful aspect.
It is most easily propagated by dividing the clumps, but it will also grow from seed. In parts of New Zealand it has spread by seed from garden centres and from domestic gardens to become a persistent weed in roadside gutter channels.
Photographs taken at Butler Creek, Picnic Bay & Gustav Creek, Nelly Bay, 2009, 2010
Page last updated 29th December 2017