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Imperata cylindrica (L.) P.Beauv. 1812
pronounced: im-per-AH-tuh sill-IN-drik-uh
(Poaceae — the grass family)
common names: Cogon Grass, Blady Grass, Satintail
Imperata is named for Ferante Imperato (1550-1625), Italian apothecary and botanist, whose name derives from the Latin imperator, emperor; cylindrica is from the Greek κυλινδρος (kylindros), a roller, cylinder.
This grass is found on all continents in tropical and warm-temperate latitudes, in a wide range of habitats, from dry sand dunes to swamps and at elevations from sea level to 2000 m, in any soil type so long as there is sufficient moisture. It is regarded as one of the world’s ten worst weeds. The patch photographed was on the vacant block of land next to the Foodworks store in Nelly Bay.
Because of its wide geographic distribution, this species exhibits much variability. A number of varieties have been named, some based on the geographic region.
It is a perennial, rhizomatous grass, putting out extensive rhizomes that give rise to spreading stems up to 3 m long and the bunches of leaf blades that grow out of the stems. These leaf blades begin at ground level and the leaves can be anything up to 120 cm long. The blades are up to 2 cm across in their widest parts, have very serrulate sharp margins, a white off-centre midrib, and are hairy at the base. Young leaves are light green, while older leaves are orange-brown to brown in colour. The ligules are brown and papery. Long panicles are produced, that eventually become fluffy-white.
Cogon grass reproduces both asexually through the clonal individuals sent up from new rhizomes, and also through sexual flowering and seed production. Flowering occurs primarily in the spring, and also in response to stress events such as burning or mowing, and the onset of the wet season. The plant is monoecious, and is an obligate out–crosser, i.e. it cannot self-fertilize. The small seeds are attached to plumes of long hairlike projections to facilitate wind dispersal, and thousands of seeds can be produced from one plant; but the species is slow to establish from seed dispersal.
This grass has the potential to dominate disturbed and marginal areas. The thick rhizome mass allows dense monotypic stands to become established. It is also suspected that the rhizomes and foliage also produce and exude allelopathic chemicals that further inhibit the growth of co-occurring native plants.
It is reported that aboriginal peoples chewed and sucked the underground stems of the plant for its sugary juice, and used the leaves for weaving dilly bags. There was a small paper industry developed in the Eumundi area (Sunshine Coast hinterland) in the early 1900s, and, locally there, the grass was used to stuff horse collars.
It is a host plant to a number of Lepidoptera, including:
• the Dusky Knight Ypthima arctous;
• the Nigger Orsotriaena medus;
• the Dingy Darter Telicota eurotas;
• the Greenish darter Telicota ancilla;
• the Orange Ringlet Hypocysta adiante;
• the Orange Streaked Ringlet Hypocysta irius; and
• the Evening Brown Melanitis leda.
It is also a habitat for frogs and many small marsupials.
Photographs taken at Nelly Bay 2013
Page last updated 17th January 2018