Sonchus arvensis is a perennial herbaceous plant. Stems can reach 4.9 ft. (1.5 m) in height and contain milky sap.
Foliage
Leaves are sessile, alternate, clasping, up to 12 in. (30.5 cm) long and decrease in size further up the stem, margins undulate with sharp spines.
Flowers
Flowering occurs in June to October, when yellow, tight, dandelion-like flower heads develop at the tips of the branches. Flowers open 2-3 hours after sunrise and close about noon.
Fruit
Fruits are reddish, ribbed and have a tuft of hair at the top.
Ecological Threat
Sonchus arvensis occurs along roadsides, railroads and other disturbed habitat. It is native to Eurasia.