The setambun is the close relative of the rambai (B. motleyana) which tastes much like the langsat or duku. The genus belongs to the family Euphorbiaceae which has important members like the Rubber tree (Hevea brasiliensis) and the important ingredients of yummy nonya kuah thickener, the buah keras (Aleurites moluccana). In Mid-March quite a number of the individuals were in flower in MacRitchie and its not easy to miss the flowering tree as the flowers, set on longish slender stalks are bunched around the trunk like a skirt (cauliflory is a term describing the position of flowers on the trunk of a tree) and give off a pleasant lemon-scent. The long stalks were laden with fruits by early June when we visited the spot again. It is noted to flower gregariously after a dry spell.
Corner, E.J.H. (1988). Wayside Trees of Malaya.Vol 1. The Malayan Nature Society, KL, Malaysia. p 274-278.