Bathurst burrs

Xanthium spinosum

Unisexual, male flowers in terminal spikes, female flowers in leaf axils. Flowers all year, mostly summer and autumn.

Annual herb to 1 m high. Stems downy, spines 0.7–2.5 cm long. Leaves with prominent veins in middle of each lobe. Straw-coloured burrs each contain two brown or black seeds.