Riding south out of Tucson, I looked for landmarks. Horizon to horizon, there was only dry flatness, dotted with ancient seafloor scrub. I was figuring I’d find real cacti – ones with those fat prickly branched stems – as I neared Tombstone. My horse was rested, well watered and fed, and the steady clip-clop of his hooves soothed me as we trotted onward.
Did I travel far back enough? Before the land was cleared for lawns, trees and shrubs? I hoped so. I couldn’t afford an allergy attack without access to 21st century medicine, and I wasn’t going back without my samples.