Epitypification of the name Epipactis purpurata Sm. (Orchidaceae, Neottieae)

The identity of the holotype of Epipactis purpurata Sm. is shown to be demonstrably ambiguous because all its flowers are at the budding stage (pre-anthesis); thus, no crucial diagnostic characters are visible, i.e., gynostemium morphology and undulations of margins of the labella and their shape and color. This way, the specimen is almost identical with several species of Epipactis genus (E. purpurata group) and including morphologically variable Epipactis helleborine, as many plants of the latter species can have similar combinations of characters like the holotype (i.e., small leaves and a robust stem even in the inflorescence). Thus, an epitype for the name Epipactis purpurata Sm. is proposed (M 257866) in order to enable its precise taxonomic interpretation and achieve nomenclatural stability.