Clematis ouachitensis, commonly known as the Ouachita leatherflower, is a species of flowering plant in the family Ranunculaceae. It is endemic to the south-central United States, where it occurs in southeastern Oklahoma and southwestern Arkansas.
Clematis ouachitensis is a perennial woody vine or climbing shrub in the Clematis subgenus Viorna. It produces nodding, urn-shaped flowers typical of the Clematis viorna species complex.
The species is characterized by membranaceous to subcoriaceous leaflets with a sparsely concentrated network of raised reticulate venation. Leaflets are typically lanceolate to ovate with acute to acuminate apices and a glabrate to moderately pubescent undersurface. Veins are relatively narrow and the areoles comparatively large.
Reproductive morphology is distinctive within the complex, including relatively short primary pedicels (typically (13.5âÂÂ38.0) mm long) that are pendulous during flowering, with flowers hanging below the subtending leaves. Sepal trichomes are relatively long, and sepal base coloration ranges from dark purple to faded lilac. Achenes are proportionally shorter, with pale to yellowish tail hairs.
Morphometric and molecular analyses have demonstrated that C. ouachitensis forms a distinct lineage within the Clematis reticulata complex.
The species is endemic to the southern Ouachita Mountains of southwestern Arkansas and southeastern Oklahoma.
Clematis ouachitensis occurs in specialized habitats including river-scour shrublands and woodlands on sandstone or shale substrates. These environments are typically well-drained and subject to periodic disturbance from flooding or erosion.
Available occurrence data indicate that the species is relatively sparsely documented, with a limited number of georeferenced records and observational occurrences.
Clematis ouachitensis inhabits open, disturbance-influenced habitats, particularly river-scour systems where periodic flooding maintains open conditions. It is adapted to rocky, well-drained substrates and occurs in ecotonal zones between shrublands and woodlands.
As a climbing vine, it depends on surrounding vegetation for support and occupies structurally open environments.
Flowering occurs from late April to late June.
The species was described in 2022 by T. Murphy and D. Estes as part of a revision of the Clematis reticulata species complex.
It represents one of several taxa segregated from a formerly broad concept of Clematis reticulata, which had historically been treated as a single, variable species. Morphometric and molecular evidence supports its recognition as a distinct lineage.
Clematis ouachitensis can be distinguished from other members of the Clematis reticulata complex by a combination of leaf morphology, pedicel length and orientation, floral traits, and geographic distribution.