We report the documentation of Tridens × oklahomensis, the naturally-occurring interspecific hybrid between Tridens flavus and Tridens strictus, from Arkansas. Collections of this uncommon hybrid were made from open, often disturbed habitat in 12 counties and observations without collections were made in 3 additional counties. All records occurred in areas with populations of both parent species. A summary of occupied site characteristics and a map of the known range within Arkansas are presented along with photographs illustrating T. × oklahomensis in comparison with both parent species. Keys, notes on habitat, and updated range maps are also presented for all known taxa of Tridens occurring in Arkansas.

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