Machaerina rubiginosa, commonly known as soft twig rush,[1] flat leaf twig rush[2] or common twig rush,[3] is a flowering plant in the sedge family, Cyperaceae, that is native to Asia and the Pacific.
The robust grass-like sedge is rhizomatous and perennial, it typically grows to a height of 4m (13feet) and a width of 21NaN1. It blooms between August and March producing brown flowers. It has rigid, terete and biconvex culms that are smooth and glabrous. The culms are 20to in length and 1to in diameter. The narrow and erect inflorescence has an interrupted-oblong shape in outline forming dense clusters that are around 7to long and with a diameter of 1to. After flowering an ellipsoid to obovoid shaped pale red-brown to bright orange coloured nut. The nut is smooth with a hispid apex with a length of 2.2to and a diameter of 1.2to.[4]
It found in swamps and on the margins of lakes and streams along coastal areas in the Mid West, Wheatbelt, Peel, South West, Great Southern and Goldfields-Esperance regions where it grows in damp silty-sandy soils. It is also found in Queensland, Victoria, New South Wales, South Australia, Tasmania and the Northern Territory.[4]
The upright foliage and spreading rhizomatous habit allow the plant to form large dense swards in wet areas. It can grow in nutrient poor soils in water up to a depth of around 50cm (20inches). The plant tends to grow taller in permanently damp areas and shorter in ephemeral environments. It is suitable for use in artificial wetlands.[5]