<i>Potentilla yokusaiana</i> var. <i>multijuga</i>, a new synonym of <i>Potentilla rhizoma</i> (Rosaceae)

The name <i>Potentilla yokusaiana</i> var. <i>multijuga</i> T. B. Lee was proposed in 1993 based on a population from Mt. Myeonsan. It has long been regarded in the Korean literature as not effectively published and, consequently, as not validly published, and has therefore been excluded from the national checklist and related taxonomic accounts. Reexamination of the publication and its protologue, however, confirms that the requirements for effective and valid publication were satisfied under the <i>International Code of Nomenclature for algae, fungi, and plants</i>. An investigation of the relevant herbarium material revealed two specimens from Mt. Myeonsan corresponding to the type gathering cited in the protologue and one specimen from Mt. Gariwangsan, a locality mentioned in the protologue. All three specimens are currently preserved in the herbarium of the Korea National Arboretum (KH). A morphological examination demonstrates that these specimens conform to the diagnostic circumscription of <i>Potentilla rhizoma</i> H. T. Im and that <i>P. yokusaiana</i> var. <i>multijuga</i> and <i>P. rhizoma</i> refer to the same taxon. Accordingly, the former name is here reduced to synonymy under <i>P. rhizoma</i>. A lectotype is designated here for <i>P. yokusaiana</i> var. <i>multijuga</i>, and nomenclatural notes are provided pertaining to the effective and valid publication and typification of this name.