prickly sowthistle

Sonchus asper is an annual or biennial herb sometimes reaching a height of 200 centimetres (6.6 ft) 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.

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. It is found in cultivated soil, pastures, roadsides, edges of yards, vacant lots, construction sites, waste areas and in grasslands.