Asteraceae

Silybum marianum

Common Names: Variegated thistle

Plant Form: Erect annual or biennial rosette herb. Size: 90 cm to 3 m tall. Stem: Stout, hollow or filled with pith, ribbed, sometimes cottony. Leaves: Shiny green with white veins and with whitish blotches (variegated) above, underneath hairy and paler, spiny on margins and over veins. Larger in rosette and more deeply lobed on stem. Flowers: Large 3-5 cm, spiny, and at the end of long stalks, numerous pink-purple tubular florets forming a head. Fruit and Seeds: Seeds are 5-8 mm long, flattened and shiny blackish with longer barbed bristles. Habitat: Pastures, roadsides, disturbed areas, woodlands. Distinguishing Features: Unlikely to be confused due to variegated leaves and general shape. Impacts: Outcompetes pasture and native species, contaminates fodder, can cause stock poisoning in high doses.