I glanced at the photograph: a teardrop shape, the size of my palm, its edges toothed with soft points curving up from stem to tip, a yellow aspen leaf. Bigtooth aspens are common in Iowa, Michigan, Wisconsin, and Minnesota, but not in Missouri, where differences in climate and soil hem their natural range. I’d been told that somewhere in Adair County, in a nature preserve called Big Creek, was the last stand of bigtooth aspen known to exist in the state. When I’d found out, I’d immediately called my mother.

“I’ve got your trees,” I told her.