This video explains an interesting and complex pollination process involving insects and milkweed. Pollination in this common plant is very similar to the pollination of Orchids. The video is designed as a resource for teaching plant biology, particularly plant-insect relationships.
Here a bee is trapped by the pollinia.
PHOTO: Edith Smith
A pollen sac is called a pollinarium.
PHOTO: Holli Webb Hearn