Asteraceae

Sonchus asper

Common Names: Prickly sowthistle

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 and prickly leaves with rounded ears at base, and from native Dune sowthistle (Sonchus megalocarpus) in having spiny leaf edges. Impacts: Competes with and contaminates crops, outcompetes native vegetation, host of pests and diseases.