• Widespread. In Australia and most Pacific island countries.
• Annual, often perennial, invasive weed found in many habitats - disturbed and cultivated land, grasslands, woodlands, forest margins, coastal areas, along roadsides, and fences. Weed of cotton,  legumes, pastures, wheat; sometimes, an escape from gardens.
• Stems, up to 2m (occasionally tree-like), branched, hairy, squarish, becoming woody. Leaves, oval, up to 10cm, pointed at both ends, short stalks, hairy. Flowers, on erect spike up to 60cm, individually small, with five white, pink or greenish petal-like structures, and leaf-like bracts below. Bracts develop pointed tips.
• Spread: spines of bracts attach to animal fur, feathers, clothes. Sent internationally for use in traditional medicines.
• Biosecurity: risk is unofficial introduction of seed and plants.Available on Internet.  Seeds (fruits) spiny, easily transported on animals/people/vehicles. Declared noxious weed in South Africa.
• Biocontrol: none.
• Cultural control: hand-weed or slashing; mulch (5-10cm) to prevent seedling growth; clean soil and seeds from machinery/vehicles; check clothing.
• Chemical control: in Fiji, glyphosate, 2,4-D, MCPA.

Devil's horsewhip; it is also known as burweed, prickly chaff flower, rough chaff flower.

Achyranthes aspera. It is a member of the Amaranthaceae.