America's favorite flora are the homey ray flowers, a tribe featuring daisies, sunflowers, chrysanthemums, dahlias, coneflowers, and black-eyed Susans, combined with the elegant, multifaceted rose. Children pick ray flowers for their prepubescent crush or for their mom; when they get older, they graduate to the rose, a more sophisticated choice. Both high culture and pop culture embrace floral imagery; think of Annie Liebovitz's famous nude photograph...