Click on images to enlarge
habit (Photo: Trevor James)
stems and leaves (Photo: Trevor James)
close-up of stem, leaf sheath and base of leaf blade (Photo: Trevor James)
close-up of underside of leaf blade (Photo: Trevor James)
young seed-head (Photo: Trevor James)
branched seed-head subtended by several leafy bracts (Photo: Trevor James)
close-up of flower spikelets (Photo: Trevor James)
close-up of mature seed-head (Photo: Trevor James)
Cyperus congestus Vahl
Mariscus congestus (Vahl) C.B. Clarke
clustered flatsedge, dense flat sedge, dense flat-sedge, dense flatsedge
Native to southern Africa (i.e. Lesotho, Namibia and South Africa).
This species is widely naturalised in the wetter regions of southern Australia (i.e. in eastern New South Wales, southern and eastern Victoria, Tasmania, south-eastern South Australia and south-western Western Australia).
It is possibly also naturalised in Brisbane in south-eastern Queensland, and is naturalised overseas in New Zealand and Hawaii.
This species, like many other sedges, is commonly a weed of roadsides, disturbed sites and damp ground. It also invades wetlands and waterways, and is regarded as an environmental weed in parts of Western Australia, Victoria, South Australia and New South Wales. It is regarded as an aquatic and wetland weed in Western Australia and listed as a moderately invasive species in WeedBase (i.e. a database of the environmental weeds of Western Australia).
Dense flat-sedge (Cyperus congestus) is also listed as an environmental weed in the wider Sydney and Blue Mountains region and in the Goulburn Broken Catchment in Victoria. In South Australia it has been recorded in the Onkaparinga River Recreation Park and is listed as a priority weed in the Pine Gully Reserve, near Adelaide.
Fact sheets are available from Department of Employment, Economic Development and Innovation (DEEDI) service centres and our Customer Service Centre (telephone 13 25 23). Check our website at www.biosecurity.qld.gov.au to ensure you have the latest version of this fact sheet. The control methods referred to in this fact sheet should be used in accordance with the restrictions (federal and state legislation, and local government laws) directly or indirectly related to each control method. These restrictions may prevent the use of one or more of the methods referred to, depending on individual circumstances. While every care is taken to ensure the accuracy of this information, DEEDI does not invite reliance upon it, nor accept responsibility for any loss or damage caused by actions based on it.
Copyright © 2016. All rights reserved. Identic Pty Ltd. Special edition of Environmental Weeds of Australia for Biosecurity Queensland.
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