On the border of extinction and speciation,<i> Polygala</i><i> seyfegoluensis</i><i> (Polygalaceae),</i> a new species from marshy habitat, Central Türkiye: Under the threat of climate change, water retreat, and subsequent degradation

Polygala seyfegoluensis Donmez, Ugurlu & Yuzb. (Polygalaceae) is herein described and illustrated as a new species from Kirsehir Province around Seyfe Lake in Central Turkiye. This new species is similar to P. pruinosa and P. supina is distinctly characterized by its prostrate habit, nearly glabrous and smaller flower parts, and an unwinged capsule. A phylogenetic analysis was conducted to show the placement of the new species within selected Polygala taxa using the trnL-F and rbcL markers. Based on the field observation, an evolutionary scenario is proposed for the new species under the driving forces of climate change, the shrinking of Seyfe Lake, and its surrounding man-made habitat. The evolutionary significance of the style and stigma of the new species and the closely related taxa has been discussed since the breeding biology. Considering the ecological issues, population size, and the accounted individuals of the new species, it is here assessed as Critically Endangered. Additionally, lectotype is selected here with a new description for the closest relative of the new species, Polygala pruinosa.