sentences:  The flowers are fragrant, dioecious or unisexual, borne singly or in threes in the leaf axils, are five- to six-petalled, white at first, changing to buff-yellow, 2.5–5 cm broad, and both sexes have central tufts of many stamens, though those of the female flowers with no viable pollen.The flowers also lack nectar.Male and female flowers appear on different plants (dioecious), and both sexes have to be planted in close proximity for fruit set.