Burr ragweed

Family: Asteraceae
Scientific name: Ambrosia confertiflora
Description: Plant Form: Erect perennial herb. Size: Up to 2 m tall. Stem: Finely hairy. Leaves: Alternate along stem, deeply twice-divided, greyish, finely hairy, up to 16 cm long. Flowers: Small greenish flowerheads up to 4 mm across, often drooping, in large clusters at the end of stems. Fruit and Seeds: Burrs with short, hooked spines, about 4 mm long. Habitat: Roadsides, wasteland, pastures, cropland. Distinguishing Features: The hooked spines on the fruit are unique among Ragweeds (Ambrosia species) introduced to Australia.

Example images for this weed