Platanthera chorisiana Cham. (Orchidaceae), a possible new member of the flora of European Russia

The article is devoted to the description of Platanthera chorisiana , an intriguing East Asiatic and North American Orchid, which was surprisingly discovered in an isolated locality in Moscow Region, although the possibility exists that the specimen might be mislabelled. This finding is discussed in the light of the presence of some other localities of this taxon, proved to be positioned outwards from its main distribution area, although not so distantly spaced. We provide analogies with other Orchids, especially with the recent sensational find of East Asiatic representative of genus Liparis in West Europe. In short, we discuss also some other peculiarities of Platanthera chorisiana , which put this species apart from other representatives of its genus.