Rosette of leaves. Key characteristics: leaves are lobed with a prominent midvein which contains a row of spines on the bottom surface.
Spines on the leaf midveins.
Vegetative plant. Key characteristics: the plant has an erect growth habit and leaves often are turned. Leaf margins have fine spines.
Seed of prickly lettuce are covered with symmetrical rows of hairs and have an appendage attached on one terminal.
Life cycle: summer or winter annual.