Photographs © Stephen Buchmann, except for the following:
p. 7 Illustration by Paul Mirocha.
p. 21 Photograph by Oleksandr Holovachov.
p. 211 With permission from Missouri Botanical Garden.
p. 254 Photograph by Retha Edens-Meier. Used with permission.
p. 260 With permission from Missouri Botanical Garden.
p. 281 Photograph by Keith Brust. Used with permission.
My thanks to Dan Bach of Bach’s Greenhouse Cactus Nursery for allowing me to borrow and photograph his plants. Thanks also to Dr. Christine Conte and Jo Falls of Tohono Chul Park (Tucson) for permission to photograph and film on the grounds of this exquisite biopark.