The Probert Encyclopaedia of Nature

LETTUCE

Lettuce is a popular name for members of the herbaceous genus Lactuca, of the family Asteraceae, family Compositae, particularly the garden lettuce, (Lactuca sativa). The genus is native to temperate regions of Eurasia and North America. The flowers, borne in panicled heads, produce feathered fruits called achenes. European wild, or prickly lettuce, (Lactuca scariola), is widely distributed throughout Europe and naturalized in the north-eastern USA. It has a slightly prickly stem, and the leaves have soft-prickled margins. European wild lettuce is thought by most botanists to be the parent species of garden lettuce. American wild lettuce, or horseweed, (Lactuca canadensis), is a smoother, leafier plant, native to temperate North America; it is common in thickets and damp borders of fields.
Research Lettuce