 Western Europe and North America were the original major markets for large @-@ scale lettuce production . By the late 1900s , Asia , South America , Australia and Africa became more substantial markets . Different locations tended to prefer different types of lettuce , with <unk> prevailing in northern Europe and Great Britain , romaine in the Mediterranean and stem lettuce in China and Egypt . By the late 20th century , the preferred types began to change , with crisphead , especially iceberg , lettuce becoming the dominant type in northern Europe and Great Britain and more popular in western Europe . In the US , no one type predominated until the early 20th century , when crisphead lettuces began gaining popularity . After the 1940s , with the development of iceberg lettuce , 95 percent of the lettuce grown and consumed in the US was crisphead lettuce . By the end of the century , other types began to regain popularity and eventually made up over 30 percent of production . Stem lettuce was first developed in China , and remains primarily cultivated in that country . 
