Romaine lettuce

Romaine or cos lettuce is a variety of lettuce (Lactuca sativa L. var. longifolia) that grows in a tall head of sturdy leaves with firm ribs down their centers. Unlike most lettuces, it is tolerant of heat.

Origin and etymology

In English, the most common name in North America is "romaine", while elsewhere it is known as "cos lettuce". Many dictionaries trace the word cos to the name of the Greek island of Cos, from which the lettuce was presumably introduced. Other authorities trace cos to the Arabic word for lettuce, khus خس [xus].

It apparently reached the West via Rome, as in Italian it is called lattuga romana and in French laitue romaine, both meaning 'Roman lettuce', hence the name 'romaine', the common term in North American English.

Cuisine

In North American supermarkets, romaine is very widely available year-round.

The thick ribs, especially on the older outer leaves, should have a milky fluid which gives the romaine the typically fine-bitter herb taste.

Romaine is a common salad green, and is the usual lettuce used in Caesar salad. Romaine lettuce is commonly used in Middle Eastern cuisine.