The leaves of Sonchus
oleraceus are deeply lobed and are broadest toward the tip. Spines on the
leaf teeth are relatively weak. Bracts below of the flower heads are smooth and
the closed heads are broadest toward the base. Plants have a milky juice.
Compare to Sonchus arvensis, which
has glandular hairs on the outside of the flower heads and narrower leaves.
Compare to Sonchus asper, which has spiny
leaves with large lobes clasping the stem and lacks glandular hairs on the flower