A new species of Polygonum sect. Polygonum (Polygonaceae) from the southwest of Türkiye

Abstract

Polygonum uysalii (Polygonaceae), a new species from the transition zone between the Mediterranean and Irano-Turanian floristic regions of Türkiye, is described based on morphological and molecular evidence. The new species is similar to P. ekimianum and P. salebrosum endemic to Türkiye, but it clearly differs by its ovate–broadly elliptic leaf (not linear–lanceolate to narrowly elliptic– suborbicular), 0.9–1.6 mm length pedicel (not 2.1–4.88 mm), dark brown ochrea at base (not pale brown), and trigonous fruit (not weakly trigonous only in upper part or ovate–elliptic). The diagnostic characters and phylogeny of the new species are discussed in terms of taxonomy and illustrations. The conservation status of the new species is also assessed based on field observations.