Prickly sowthistle

Family: Asteraceae
Scientific name: Sonchus asper
Description: Plant Form Annual or biennial rosette herb. Size 20 cm to 2 m tall. Stem Smooth, green, with a few glandular hairs. Leaves Up to 20 cm long, entire to dissected, the upper ones with rounded ears at base and pungent spines along the edges. Flowers Dandelion-like, yellow flowerheads 5-6 mm across, with naked or glandular leaves underneath. Fruit and Seeds 2-3 mm long, flattened, with three ribs on surface, and parachuting hairs up to 9 mm long. Habitat Roadsides, cultivated areas, disturbed land. Distinguishing Features Differs from Common sowthistle (Sonchus oleraceus) in its more leathery leaves with rounded ears at base (versus soft with pointy ears) and from native Dune sowthistle (Sonchus megalocarpus) in the spiny leaf edges (versus only toothed). Impacts Competes with and contaminates crops, outcompetes native vegetation, host of pests and diseases.

Example images for this weed