Is Epipactis pseudopurpurata distinct from E. purpurata (Orchidaceae)? Evidence from morphology, anatomy, DNA and pollination biology

Abstract

A comparative analysis of the main distinctive features of Epipactis pseudopurpurata, according to the protologue, and E. purpurata revealed that the absence or disappearance, as well as the atrophy, of a viscidium is typical and characteristic of young ramets of E. purpurata and can also result from its removal by pollinators and other insect visitors. The gynostemium morphology is similar in both species examined. The minor differences in its shape are an indication of developmental variability. The morphology of numerous ramets of E. purpurata and of their gynostemia corresponds to Mered'a's description of E. pseudopurpurata, suggesting phenotypic plasticity in the former species. Based on comparative analyses of both taxa, including molecular data, the authors propose to synonymize E. pseudopurpurata with E. purpurata in view of the low value of the taxonomic features distinguishing the two species.