The durian is the fruit of several tree species belonging to the genus Durio and the Malvaceae family. Widely known and revered in southeast Asia as the "king of fruits", the durian is distinctive for its large size, unique odour, and formidable thorn-covered husk. The fruit can grow as large as 30 centimetres (12 in) long and 15 centimetres (6 in) in diameter, and it typically weighs one to three kilograms (2 to 7 lb). Its shape ranges from oblong to round, the colour of its husk green to brown, and its flesh pale yellow to red, depending on the species.
The edible flesh emits a distinctive odour, strong and penetrating even when the husk is intact. Some people regard the durian as fragrant; others find the aroma overpowering and offensive. The smell evokes reactions from deep appreciation to intense disgust. The odour has led to the fruit's banishment from certain hotels and public transportation in southeast Asia.
The durian, native to Brunei, Indonesia and Malaysia, has been known to the Western world for about 600 years. The 19th-century British naturalist Alfred Russel Wallace famously described its flesh as "a rich custard highly flavoured with almonds". The flesh can be consumed at various stages of ripeness, and it is used to flavour a wide variety of savoury and sweet edibles in Southeast Asian cuisines. The seeds can also be eaten when cooked.
There are 30 recognised Durio species, at least nine of which produce edible fruit. Durio zibethinus is the only species available in the international market: other species are sold in their local regions. There are hundreds of durian cultivars; many consumers express preferences for specific cultivars, which fetch higher prices in the market.