Asteraceae

Onopordum acanthium

Common Names: Scotch thistle

Plant Form: Erect biennial herb. Size: Up to 2 m tall. Stem: Erect, with wings up to 1.5 cm wide, and spines to 5 mm long. Woolly or cobwebby appearance. Leaves: Grey-green, spiny, egg to lance-shaped, up to 35 cm long. Flowers: White to purple heads up to 6 cm diameter. Fruit and Seeds: Brown-grey 4-5 mm long, ribbed with hairs on top. Habitat: Pastures, irrigated and dryland cropping areas. Distinguishing Features: Similar to other Onopordum species, but with a stem unlike Stemless thistle (Onopordum acaulon), and with deeper lobed leaves and more woolly stems than Illyrian thistle (Onopordium illyricum). Impacts: Reduces land productivity, contaminates grain and seed, can reduce wool value.