There are several types or cultivars of lettuce. Three types – leaf, head and cos or romaine – are the most common. Leaf lettuce - Also known as looseleaf, cutting or bunching lettuce, this type has loosely bunched leaves and is the most widely planted. It is used mainly for salads. Romaine/Cos lettuce - Used mainly for salads and sandwiches, this type forms long, upright heads. Head lettuce - Distinguished by leaves arranged in a dense rosette which ultimately develops into a head. Iceberg lettuce, butterhead belong to this group. Chinese lettuce (L. sativa var longifoliaf) - Also called A Choy, AA Choy, You Mai Cai (Chinese mandarin), Yau Mak Choy, Yu Mak Choy, grown mainly for its leaves. The leaf is long and sword-shaped with a bit bitter taste. Celtuce (L. sativa var. asparagina) - Also called Chinese stem lettuce or Wo Sun (Chinese mandarin), grown primarily for stem. https://agrohaitai.com/collections/celtuce .