Kevin Schafer / Rosy Periwinkle (Catharanthus roseus) leaves and flowers used for anti-cancer medicine, Madagascar

Ingo Arndt / Rosy Periwinkle (Catharanthus roseus) pair in bloom, plants are harvested for medicinal use, Madagascar

Ingo Arndt / Rosy Periwinkle (Catharanthus roseus) in bloom, plants are harvested for medicinal use, Madagascar

Pete Oxford / Isalo National Park with Rosy periwinkle (Catharanthus roseus) in bloom in foreground and Sandstone Massif in background, MADAGASCAR

Pete Oxford / Isalo National Park with Rosy periwinkle (Catharanthus roseus) in bloom in foreground and Sandstone Massif in background, MADAGASCAR

Doug Wechsler / Madagascar / Rosy periwinkle (Catharanthus roseus)source of cancer cure, Madagascar

Pete Oxford / Rosy Periwinkle (Catharanthus roseus) a medicinal plant in bloom, Isalo Massif, Isalo National Park, Madagascar

Gerry Ellis / Rosy Periwinkle (Catharanthus roseus) in bloom, plants are harvested for medicinal use, Madagascar

Pete Oxford / Madagascar periwinkle (rosy) {Catharanthus roseus} Madagascar source of cancer drug