Abstract
Phedimus individuals from Mt. Daeam, once referred to as Phedimussikokianus, exhibit certain morphological characters that are unique within the genus. Phedimus is one of the most notorious groups for taxonomic problems due to the high morphological variation found in leaf shape, stem numbers, phyllotaxis and seed structure. Taxa in Phedimus also easily hybridize, further leading to taxonomic confusion. To carefully confirm the identity of the putative new species from Mt. Daeam, we examined morphological characters from ~100 herbarium sheets of six closely related Phedimus species. A molecular phylogenetic approach was also employed to delimit the species boundary and infer the phylogenetic relationships among the seven Phedimus species, including the species from Mt. Daeam. Both morphological and molecular phylogenetic results indicated that the species found on Mt. Daeam is a new species that is more closely related to P.middendorffianus and P.takesimensis than to the remaining four Phedimus species. Here, we provided a full description of the new species P.daeamensis as well as an updated key for the seven Phedimus species examined.