At the Serpentine, a Show of Nature’s Healing Power. Art, Flowers and Plants, Endangered and Extinct Species, Gardens and Gardening, Global Warming, Levees and Dams, Serpentine Galleries, Global Witness, Eno, Brian, Obrist, Hans Ulrich, Metzger, Gustav (1926-2017), Colombia, Elwha River (Wash), London (England), The Overstory (Book)