title: [Sibling species of rein orchid (Gymnadenia:Orchidaceae, Magnoliophyta) in Russia].
abstract: Recent molecular phylogenetic studies of the genus Gymnadenia have demonstrated that it contains sibling taxa, i.e., species that are hardly distinguishable according to morphological traits, yet are phylogenetically rather distant and distinctly distinguishable by molecular methods, which is a rare phenomenon for angiosperms. The sequencing of the ITS 1-5.8S rDNA-ITS2 fragment allowed us the presence of the species G. densiflora to be demonstrated in Russia. The Russian specimens have confirmed a high degree of genetic differentiation between G. conopsea s. str. and G. densiflora, which proves their taxonomic status rank of species. Morphological analysis has shown that the features that allow for the best discrimination between these two species in Northwestern Russia are the length of the lower bract, length of the mid-lobe of the lip, and width of leaves. The ecological and phenological discrimination between G. conopsea s. str. and G. densiflora is briefly reviewed. The ITS sequence variation in these species has been analyzed; the molecular genetic distinctions of the G. conopsea individuals from the eastern part of the distribution area have been discovered for the first time. Different taxonomic interpretations of the Gymnadenia phylogenetic tree topology taking into account the presence sibling species are discussed in general.
authors.forename: P G
authors.initials: PG
authors.lastname: Efimov
mesh_terms: D004275:DNA, Ribosomal / Q000235:genetics; D049810:Genetic Speciation; D014644:Genetic Variation; D029595:Orchidaceae / Q000235:genetics*; D010802:Phylogeny; D012426:Russia; D017422:Sequence Analysis, DNA
chemical_list: D004275:DNA, Ribosomal