Asteraceae

Xanthium strumarium

Common Names: Noogoora burrs

Plant Form: Annual herb. Size: To 1.2 m tall. Stem: Spineless, with bristly hairs. Leaves: Mostly heart-shaped to triangular in outline, weakly lobed, irregularly toothed, up to 18 cm long-stalked, with bristly hairs. Flowers: Inconspicuous, clustered, whitish to greenish flowerheads. Fruit and Seeds: Burrs 7-20 mm long, not hairy, with many hooked spines on surface and two equally long, straight beaks at the end. Habitat: Farmland, roadsides, wastelands, and riverbanks. Distinguishing Features: Stems are spineless compared to Bathurst burr (Xanthium spinosum) which has three long sharp spines on the stem at the base of each leaf. Impacts: Outcompetes and replaces native vegetation, burrs contaminate wool, pollen may cause hayfever symptoms.