Worldwide distribution. In Australia, New Zealand, most Pacific island countries.
Major invasive weed. Produces abundant seed. Invades many crops (e.g., cotton, maize, soybean, sugarcane), wastelands, natural vegetation, roadsides; spreads pests (midge, viruses, fungi, bacteria); toxic to livestock (especially after drought); fire risk. Allergenic pollen. Produces root chemicals inhibiting competitors.
Numerous erect stems up to 3m, from extensive, purple-spotted scaly, rhizomes. Leaves hairless with prominent white midribs. Pale green-purplish, branched flower seedheads, up to 35cm. Spikelets (flowers) in pairs or triplets along and at end of branches.
Spread: rhizomes and seed on the wind, water, seed lots, fodder, vehicles. Rhizomes assist survival.
Biosecurity: check for seed in livestock fodder, maize and sorghum seeds.