Dioecious: unisexual male and female flowers occur on separate plants. (Unisexual: same as imperfect, a flower has only stamens or only pistils.)
Monoecious: unisexual male and female flowers occur on the same plant.
Hermaphroditic: a plant with bisexual flowers. (Bisexual: same as perfect, flower with both male and female structures (stamens and pistils).
Polygamous: plant with both bisexual and unisexual flowers.