Save. Leo Valen. The filament of a flower is one of the male reproductive parts of the plant. When a flower opens, the filaments can be seen inside, thrusting up like stems within the flower itself.A filament is topped by the anther. Together the anther and filament make up the flower's stamen.eo Valen. The filament of a flower is one of the male reproductive parts of the plant. When a flower opens, the filaments can be seen inside, thrusting up like stems within the flower itself.