Clematis pedunculata (Ranunculaceae), a new species from Korea previously confused with C. fusca var. violacea

During a taxonomic revision of Clematis in Korea, Korean plants previously assigned to C. fusca var. violacea Maxim. were found to comprise two morphologically distinct groups. To assess the taxonomic significance of this variation, living plants and 452 herbarium specimens were examined, and maximum-likelihood phylogenetic analyses were performed based on sequences from the nuclear ribosomal internal transcribed spacer (ITS), the plastid matK gene, and the atpB–rbcL intergenic spacer. One of these groups is described here as Clematis pedunculata B. K. Park, sp. nov . The new species is distinguished from other Korean members of the C. fusca complex by a combination of an androdioecious sexual system, smooth to shallowly grooved stem internodes that are sparsely villous to glabrate, conspicuous peduncles 1.5–12.1 cm long, and stamens bearing short whitish hairs. In the ITS phylogeny, the three accessions of C. pedunculata formed a moderately supported clade distinct from the sampled Korean members of the C. fusca complex, although their deeper phylogenetic placement was weakly resolved. In the combined plastid phylogeny, they formed a distinct clade with moderate support, separate from all sampled Korean members of the complex. The concordant morphological and molecular evidence supports the recognition of C. pedunculata as a distinct species currently known only from South Korea.