Blue Setchellanthus

Setchellanthus caeruleus is one of botany's great loners, the single living species in its own plant family, Setchellanthaceae, found nowhere on Earth but a handful of dry limestone valleys in south-central Mexico. Unlike so many of its desert-dwelling neighbors, it never wove itself into local herbal, culinary, or craft tradition, and no historical record credits any part of it with medicinal or food use among the region's communities. Its real story belongs to botanists, who puzzled for nearly a century over where to place it before DNA studies finally confirmed it deserved a family entirely of its own. What traditional value it holds today is quiet and ecological, a small, thorny anchor of the Tehuacán-Cuicatlán drylands that turns sky blue after the rains and asks little of the people who pass it by.