Taxonomic revision of the formerly monotypic orchid genus Dactylostalix

The Calypsoinae orchid genus Dactylostalix , previously considered a monotypic genus endemic to Japan and the Russian Far East (the Kuril Islands and Sakhalin Island), is now redefined to encompass two species. This reclassification is based not only on the examination of type specimens and literature but also on molecular data. While Pergamena uniflora has long been regarded as a synonym of Dactylostalix ringens , it is distinguishable by its shorter scape, smaller flower, less spotted tepals, drooping sepals and lateral petals, labellum with smaller, narrowly triangular to ovate lateral lobes, more distinct keels on the adaxial surface of the lip, and a slender column with a smaller stigma and weakly developed clinandrium. We propose the new combination Dactylostalix uniflora , recognizing it as a distinct species within the genus Dactylostalix . Phylogenetic analysis utilizing genome-wide markers has also demonstrated that the two species are genetically distinct. Our findings, obtained through the integration of morphological data and molecular phylogenetics, indicate that D. uniflora represents a distinct evolutionary lineage from D. ringens. Examination of type specimens has led us to conclude that Calypso japonica , Dactylostalix maculosa , and Dactylostalix ringens f. punctatus are junior synonyms of D. ringens . Additionally, we designate the lectotypes for P. uniflora (= D. uniflora ), C. japonica , and D. maculosa .