Careful observations of flowers will yield many surprising ideas concerning the possible functions of their widely varied colors and shapes. Remember that flowers in nature exist only to propagate the species and not to please us. Therefore their primary purposes must be to attract pollinators (assuming they are not wind pollinated), to set, and disperse the seeds.
Three examples of wildflowers that we have blooming on our farm in late July well illustrate the diversity and beauty of flowers. Lilies are one of the larger and more beautiful flowers and I recently found this single Carolina lily plant growing in a small gap in the forest created about five years ago when a bulldozer made a forest access road. I have not observed any pollinators but consider the arrangement of the very long stamens (containing the pollen filled anthers at the tips) and the style (containing the stigma at the tip which receives the pollen). This flower which hangs down is obviously designed for hovering pollinators such as hummingbirds, or large butterflies or sphinx moths, which would contact the anthers and stigma as they come in to feed on nectar. Smaller insects would bypass the reproductive mechanisms and in essence steal the nectar.
In complete contrast, consider the flower of a wild swamp rose that grows on our front fence. It is relatively flat with very short stamens. Most roses do not provide nectar as a reward to potential pollinators but instead attract beetles or in this case bumblebees which virtually wallow in the massed anthers and collect pollen on their hairs. The bumblebees also move around rapidly and vibrate, which may release the pollen. This wild rose, and indeed the exotic and invasive multiflora rose, are far more attractive and beneficial to insects and birds than the hybrid roses which are widely planted in gardens. Indeed I often see our hummingbirds, attracted to the bright red flowers of knockout roses, go away disappointed by the lack of nectar.
A brilliant red native flower that is found in wet areas that are disturbed and thus early successional, is the cardinal flower. Here is a brightly colored flower that would seem to be designed even more specifically than the lily to attract hummingbirds. The nectar is available down a thin corolla tube, and the reproductive parts are concentrated in a structure at the top of the flower. Clearly this would contact the head and/or back of the hummingbird as it feeds on the nectar. Access would be difficult for other animals. Why would it be advantageous for a flower to be so specialized for a single group of animals or in this case a single species of bird? Apparently hummingbirds are very efficient at pollinating plants since they visit them repeatedly (a process called trap-lining) and accomplish a high degree of fertilization.
So enjoy the beauty of flowers simply for the colors and fantastic forms, or go beyond this simplistic appreciation and see how much more amazing they are when you think about why each flower has evolved its unique colors and shapes.
Bill Dunson, Englewood, FL & Galax, VA