Swan Flower (Aristolochia erecta)

Close-up of flower and leaves.

The Swan Flower is one of many members of the Aristolochiaceae (Birthwort family) that have their flowers pollinated by temporarily trapping insects. Many aristolochias have rotten smelling flowers to attract flies. The insects fly into the flowers and are trapped by downward facing hairs in the tube of the flower. They move about in the "bottom" of the flower where the anthers are located and pick up pollen. Soon, the flower wilts and the flies can escape to go pollinate another aristolochia flower.

Above scan and text by Charles Crauford