Oxystegus daldinianus (De Not.) Köckinger, O.Werner & Ros, a species recently identified from the Alps of central Europe, is reported as new to the New World from collections in North Carolina, U.S.A., with a key to species of the genus in North America. A refugial explanation is proffered for this montane disjunction. Species distinctions in Oxystegus and evolutionary relationships are evaluated with two tools—an analytic key, and support measured with sequential Bayes-based information theory.