Prickly lettuce; Lechuga silvestre

The closest wild relative of cultivated lettuce (Lactuca sativa).
1 to 1.5 m. high annual or biennial plant. It has a hairless spiny reddish stem, containing a milky latex. The leaves grow along the spiny stem, are oblong lanceolate, often pinnated (especially for the lower leaves), waxy grey green. Fine spines are along the edges. The undersides have whitish veins. They get progressively smaller as they reach its top and emit latex when cut.

The flower heads are 11 to 13mm wide, are pale yellow, often tinged purple. Many flowers are produced and usually appear in the upper part of the plant.