Sonchus arvensis
Sonchus arvensis, the field milk thistle, field sowthistle,perennial sow-thistle, corn sow thistle, dindle, gutweed, swine thistle, or tree sow thistle, is a species of flowering plant in the daisy family Asteraceae. S. arvensis often occurs in annual crop fields and may cause substantial yield losses. The plant grows up to 1.5 metres (4 ft 11 in) in height, 744 with leaves 10–35 cm (4–13+3?4 in) long and 4–14 cm (1+1?2–5+1?2 in) wide. It produces conspicuous yellow flowerheads about 3–5 cm (1+1?4–2 in) wide, which are visited by various types of insects—especially hoverflies of the genus Eristalis.