Romaine lettuce is very green
Romaine lettuce
Romaine or cos lettuce ("Lactuca sativa" L. var. "longifolia") is a variety of lettuce that grows in a tall head of sturdy dark green leaves with firm ribs down their centers. Unlike most lettuces, it is tolerant of heat. In North America, romaine is sold as whole heads or as “hearts” that have had the outer leaves removed and are often packaged together. 
Commercially sold romaine lettuce has historically been the subject of product warnings by both U.S. and Canadian health authorities
lettuce was associated with the ancient Egyptian god of fertility, Min, for its resemblance to the phallus.
Romaine lettuce may be used in the Passover Seder as a type of bitter herb. It symbolises the bitterness inflicted by the Egyptians while the Israelites were slaves in Egypt.
Cuisine.
Romaine is a common salad green, and is the usual lettuce used in Caesar salad. Romaine lettuce is commonly used in Middle Eastern cuisine. Romaine, like other lettuces, may also be cooked. For example, it can