Per Item. Class 1. Local/English.Romaine or cos lettuce is a variety of lettuce that grows in a tall head of sturdy dark green leaves with firm ribs down their centres. Unlike most lettuces, it is tolerant of heat. It has a subtle, buttery sweet flavour, perfect for sandwiches. Cos is the traditional choice for Caesar salad. The long, light-to-dark green leaves are characterised by ‘ribbing’. Cos lettuce adds a sweet, hardy crunch to any salad or sandwich.