Lactuca Linnaeus. Lettuce.
A genus of about 75 species, herbs, nearly cosmopolitan (especially north temperate).
ID notes: Most species are highly variable in leaf lobing. Note that L. serriola can be mistaken for Sonchus, but L. serriola has prickles on the midrib, while the prickles of Sonchus are restricted to the leaf margins.
Ref: Cronquist (1980); McVaugh (1972); Strother (2006r) In Flora of North America Editorial Committee (2006a). Show full citations.