Panicum effusum

Panicum effusum, hairy panic, is a tufted, short-lived perennial C4 grass in the family Poaceae native throughout mainland Australia and extending into New Guinea, where it occurs across virtually every habitat from tropical rainforest margins through inland woodlands and seasonally dry grasslands to semi-arid shrubland on low- to medium-nutrient clay soils overlying shale or conglomerate. Plants form open tussocks of slender, ascending culms up to about 70 cm tall, the flat leaf blades 5 to 30 cm long and 0.4 to 1 cm wide and conspicuously clothed in scattered tubercle-based hairs. The diffuse, pyramidal terminal panicle 5 to 50 cm long bears many small, two-flowered, smooth, glabrous spikelets on fine spreading branches. The C4 photosynthetic pathway gives the species a strong advantage in hot, dry conditions, and at extreme drought the whole inflorescence breaks at the base and becomes a tumbleweed, distributing seed by rolling and occasionally piling against fences and buildings in inland towns.