Lansium parasiticum (syn. Lansium domesticum), also known as langsat (/ˈlɑːŋsɑːt/) or lanzones, is a species of tree in the Mahogany family. The plant, which originates from western Southeast Asia, bears edible fruit. It is the provincial flower for the Indonesian province of South Sumatra.
The tree is average sized, reaching 30 metres (98 ft) in height and 75 centimetres (30 in) in diameter. Seedling trees 30 years old planted at 8 x 8 meter spacing can have a height of 10 meters and diameter of 25 cm. The trunk grows in an irregular manner, with its buttress roots showing above ground. The tree's bark is a greyish colour, with light and dark spots. Its resin is thick and milk coloured.
The pinnately compound leaves are odd numbered, with thin hair, and 6 to 9 buds at intervals. The buds are long and elliptical, approximately 9 to 21 centimetres (3.5 to 8.3 in) by 5 to 10 centimetres (2.0 to 3.9 in) in size. The upper edge shines, and the leaves themselves have pointed bases and tips. The stems of the buds measure 5 to 12 millimetres (0.20 to 0.47 in).