abstract:Sonchus asper (Sharp-fringed Sow Thistle, Prickly Sow Thistle, Spiny Sow Thistle, or Spiny-leaved Sow Thistle) is an annual plant 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.