Sonchus asper, the prickly sow-thistle,[2] rough milk thistle,[3] spiny sowthistle,[4] sharp-fringed sow thistle, or spiny-leaved sow thistle, is a widespread plant in the dandelion tribe within the daisy family.
Sonchus asper is an annual or biennial herb sometimes reaching a height of 200 cm (almost 7 feet). with spiny leaves and yellow flowers resembling those of the dandelion. The leaves are bluish-green, simple, lanceolate, with wavy and sometimes lobed margins, covered in spines on both the margins and beneath. The base of the leaf surrounds the stem. The leaves and stems emit a milky sap when cut. One plant will produce several flat-topped arrays of flower heads, each head containing numerous yellow ray flowers but no disc flowers.[5][6]
Sonchus asper is native to Europe, North Africa, and western Asia. It has also become naturalized on other continents and is regarded as a noxious, invasive weed in many places. Its edible leaves make a palatable and nutritious leaf vegetable.[7][8][9][10][11]