Species that have responded to rising temperatures by flowering earlier – on average, seven days earlier than Thoreau recorded – have managed to survive. Those that did are dying off, including many familiar families such as orchids, irises, sunflowers, dogwoods, lilies, roses, and buttercups.
Because so many of the winners and losers have been found to be phylogenetically linked (meaning they are close genetic relatives), the study is the first to report that whole groups of related plants are at extinction risk from global warming, the researchers said.