Citrus hystrix, commonly known as kaffir lime, is a tropical fruit tree native to Southeast Asia. It is characterized by its bumpy, dark green fruit and aromatic leaves, which are widely used in cooking, particularly in Thai and Indonesian cuisines. The tree typically grows to about 3 to 5 meters in height and thrives in warm, humid climates. The leaves of Citrus hystrix are unique, as they are double leaves that are glossy and dark green. They are often used fresh in dishes for their distinct flavor and fragrance. The fruit, while not commonly eaten raw due to its strong bitterness, is used to make essential oils and in traditional medicine.