Plant Form Erect annual or biennial herb. Size Up to 2 m tall. Stem Erect, with wings up to 1.5 cm wide, and spines to 5 mm long. Slightly woolly or cobwebby appearance. Leaves Grey-green, spiny, deeply lobed, lance shaped, up to 55 cm long. Flowers Purple heads up to 6 cm diameter, surrounded by spiny bracts. Fruit and Seeds Brown, 4-angled, wrinkled capsules. Habitat Pastures, irrigated and dryland cropping areas. Distinguishing Features Similar to Scotch thistle (Onopordum acanthium), but less cobwebby in appearance, and generally larger flowerheads. There are hybrids however. Impacts Reduces land productivity, contaminates grain and seed, can reduce wool value.