Which lime leaves are listed among common flavors in Thai food?

The lime leaves listed among common flavors in Thai food are kaffir lime leaves, also called makrut lime leaves.

These aromatic leaves come from Citrus hystrix, a citrus tree native to tropical Southeast Asia. Thai cooks use the leaves fresh, dried or frozen, most often to add a strong, floral citrus fragrance rather than straightforward sourness. They commonly appear in tom yum, curries, soups and curry pastes.

The leaves are often torn, shredded or bruised to release their essential oils. They may be simmered whole and removed before eating, or finely sliced as a garnish. Their flavor is distinct from ordinary Persian lime leaves and from the leaves of curry plants, bay trees or banana plants.

The same tree supplies both leaves and a strongly ridged fruit. Its rind is used in Thai and Lao curry pastes, while the fruit and leaves are also important in Cambodian, Indonesian, Malaysian and Vietnamese cooking. The term “kaffir” is increasingly avoided by some publishers because of its offensive associations, so “makrut lime” is a common alternative.