Flowers in the lily family usually have six equal-sized petals that form a showy, trumpet-shaped flower. Often the petals are curved back to reveal six long stamens and a style that protrude from the flower's throat. These are the flower's reproductive organs involved in pollination. In the garden, insects and hummingbirds usually pollinate lilies. You can also hand-pollinate lily flowers, but don't expect many seeds if you're crossing hybrid lilies.
To understand lily pollination, understand the flower's structure. The petals form a visual signal that attracts pollinators -- insects and birds -- to the flower, so when they visit it they will touch the reproductive organs, transferring pollen from plant to plant. The six stamens are the male reproductive organs. Each stamen consists of a long stalk coming from the flower's base and topped by a prominent anther that produces pollen. The female reproductive organ, called the pistil, emerges from the center of the flower. At its base is a small, green, sausage-shaped ovary. The sticky pistil tip is the stigma, and it receives the pollen grains during pollination.
Pollination refers to the transfer of pollen from flower to flower. What's really important is what happens after that. When a pollen grain lands on the stigma, if it is compatible with the flower it landed on, it grows a pollen tube down the pistil into the ovary, where it fertilizes one of the ovules and a seed forms. In this way, pollination is essential for the survival of a species through seed production. Once fertilized, the ovary starts to grow, the petals fall off, and a seed pod forms.
Bees and moths are lily flowers' primary insect pollinators. Flowers that attract bees tend to be brightly colored with rigid, inflexible stamens and anthers to support the bee's weight. Flowers for moths are usually white, with a sweet scent and flexible stamens. The bamboo lily (Lilium japonicum) is visited by both moths and bees and grows in U.S. Department of Agriculture plant hardiness zones 4 through 8. White trout lily (Erythronium albidum), which also grows in USDA zones 4 through 8, has a downward-pointing flower with tightly bunched stamens and stigma, suited for its bumblebee pollinator. Moths pollinate Madonna lily (Lilium candidum), which grows in USDA zones 5 through 9. An example of a hummingbird-pollinated lily is Turk's cap (Lilium superbum) with yellow to yellow-orange downward-pointing flowers. It grows in USDA zones 5 through 8.
Most garden lilies are hybrids and have chromosome configurations that don't lend themselves to seed formation. For better seed production, make crosses within or between pure species of lilies. Transfer pollen with a clean cotton swab. Select a female parent flower and, using tweezers, remove all six stamens, taking care not to get any pollen on the stigma. Choose the male parent. Look for a newly opened flower with an anther that has fresh, fluffy new pollen. Dab the swab on the anther to collect some of the pollen. Take it immediately to the female parent. Rub the swab's pollen-coated area on the stigma's surface and check to see that some of the pollen is sticking to it. If you wish, label the female parent with a hang tag attached beneath the flower and record the cross information in a notebook.