Xerophile: Cactus Photographs from Expeditions of the Obsessed (Revised Edition):

Finally back in print, Xerophile: Cactus Photographs from Expeditions of the Obsessed brings together eighty years of plant pics from some of the world’s most remote habitats: a bizarre two-leaved gymnosperm that lives for millennia in the deserts of Namibia, a succulent whose baneful sap is used by hunters to fell large game in Angola, cactus that populate the snow-covered peaks of Bolivia, that sink below ground to survive drought in Mexico, that are pollinated by bats in Brazil, and that grow on pure lava fields in the Galápagos... all mined from the dusty old slide carousels of twenty-five xeric plant obsessives; from PhD botanist, to banker, to highschool art teacher, to cancer researcher... you get the idea.   

This newly revised edition also includes a new section of notes on the photographs.