L. sativa includes all the lettuce cultivars: cos or romaine, leaf lettuce, butterhead, iceberg or crisphead and others.
The first evidence that the cultigens L. sativa had been developed under domestication comes from paintings in Egyptian tombs beginning about 4500 B. C and continuing through the Old and Middle Kingdoms.
Egyptologists interpret these as representing the primitive romaine or cos cultigen.
It is possible that cultivation was begun for the sake of the seeds which is contain excellent edible oil.
Clear historical records cultivated lettuce begin in Greece about 450 B. C and continue through later Greek sources, including Aristotle.
In Rome, various cultivars were recorded by the 1st century A. D and the crop was evidently already common, as it has remained on the Mediterranean region in general.
The spread of L. sativa eastward is obscure. Herodotus mentions it as fare for Persian royalty about 660 B. VC and the species has long been grown in northern India under a Persian name. Different authorities place its introduction to China in the 5th and 7th centuries A. D.
A distinctive cultivar, called stem lettuce, was selected in China.
The Romans presumably introduced cultivation to northern Europe, where it was grown in summer rather than as a winter annual.
It survived the Middle Ages in obscurity. It has been mentioned it in England, and it is well documented in the 16th an 17th century herbals in various countries, the varieties including cos, leaf and head lettuce.
During the 17th and 18th centuries, selection of mutants in Europe gardens resulted in great proliferation of the name varieties especially of France, Holland and England.
Meanwhile, L. sativa had been widely introduced to the New World tropics. The Spaniards were growing it in Hispaniola by 1494 and soon after elsewhere in the West Indies and on the mainland Portuguese, French an other European introduces it to their tropical American colonies early in the colonial period.
The crop was easily grown and usually produced seed in both lowland and highland tropical climates.
However, lettuce does not seem to have been taken seriously by most American Indian groups.
Some of them in the Andes grew it mainly as fodder or their Guinea pigs.
Lactuca sativa – Lettuce
