David George Haskell, a professor of biology, is already way down this track. “When we take pleasure in a flower,” he says, “we reclaim our inheritance as animals.” He has written widely loved books about the secrets of forests and the sounds of the living world and now, in “How Flowers Made Our World” — a rather inert title for a work of real passion — has become the advocate for the enormous silent presence of flowering plants in almost every nook and cranny of our lives.