How does dioecism differ from bisexual flowers in Sapindales plants?

In the plant order Sapindales, the primary distinction between bisexuality and dioecism lies in the distribution of reproductive organs:1

• Bisexual flowers: These represent the typical floral state where both male (stamens) and female (pistils) reproductive structures are present and functional within a single flower.1
• Dioecism: This is a condition where male and female flowers are borne on entirely separate individual plants.1

While many Sapindales exhibit a trend toward obligate cross-pollination, most have not achieved complete anatomical dioecism. Instead, the order displays a spectrum of reproductive strategies:1

• Polygamous plants: Many species possess both bisexual and unisexual flowers on the same individual plant.1
• Functional unisexuality: Some flowers appear structurally bisexual but are functionally unisexual because the stamens fail to produce fertile pollen or the pistils do not contain viable ovules.1
• Rudimentary organs: In many unisexual flowers within this order, the nonfunctional organ (either the pistil or the stamens) often remains as a rudimentary, sterile remnant.1