First record of Balkan Thymus jankae (Lamiaceae) from Ukraine, with taxonomic remarks on the species

The Balkan species Thymus jankae is documented for the first time from Ukraine on Mount Chorna Hora (Vynohradiv town, Transcarpathian region), which is ca. 300 km northwards from its main range. This species locality has long been overlooked due to misidentification of its early collections with other Thymus taxa. Despite its ambiguous taxonomy, available morphological, caryological, biogeographical, and molecular data support a species rank of Th. jankae and suggest its ancestral position within the Thymus praecox-group. Morphology and chromosome count (2n = 56) of plants from Ukraine are congruent with the data available for Balkan populations. Phytosociological survey of Th. jankae locus in Ukraine shows the species to be affiliated with the associations Alysso alyssoidis-Sedetum and Festucetum pseudodalmaticae, as well as a community physiognomically close to the association Potentillo heptaphyllae-Festucetum rupicolae. The first two associations are parts of biotopes (6110 and 6240) with priority status according to Annex I of the Habitats Directive (92/43/EEC) and represent respectively a pioneer community and subpannonic meadow steppe grassland with evident southern European relationships. Most likely, the discovered locality of Th. jankae is a relict northern outpost created by extinction of a part of the former species range, although its anthropogenic origin should not be also excluded. Conservation of Th. jankae in Ukraine on the national level is discussed.