Matos and Rudolph (1985) report several species found in the Roy E. Larson Sandylands Sanctuary, part of the Big Thicket, Hardin County, Texas, as endemics to Texas (endemics to Texas and Oklahoma in one case). Hardin County is about 30 km west of the Louisiana border and the habitat is continuous from east Texas into Louisiana. Endemism in state terms is unlikely in such situations.