Albizia lebbeck is a species of Albizia, native to tropical southern Asia, and widely cultivated and naturalised in other tropical and subtropical regions. English names for it include Lebbeck, Lebbek Tree, Flea Tree, Frywood, Koko and Woman's tongues Tree. The latter name is a play on the sound the seeds make as they rattle inside the pods. Being one of the most widespread and common species of Albizia worldwide, it is often simply called "siris" though this name may refer to any locally common member of the genus.
It is a tree growing to a height of 18-30 m tall with a trunk 50 cm to 1 m in diameter. The leaves are bipinnate, 7.5-15 cm long, with one to four pairs of pinnae, each pinna with 6-18 leaflets. The flowers are white, with numerous 2.5-3.8 cm long stamens, and very fragrant. The fruit is a pod 15-30 cm long and 2.5-5.0 cm broad, containing six to twelve seeds.