Taxonomic description and phylogenetic placement of a new xanthogalum species (Apiaceae) from Turkey

The genus Xanthogalum, represented by the species X. purpurascens and X. turcicum in Turkey, forms a small but taxonomically significant group characterized by decurrent leaves and large fruits with broad, undulate wings. During extensive field surveys (2020–2025) in northeastern Turkey, a distinctive population was discovered exhibiting a combination of morphological characters not found in any previously described Turkish species. Xanthogalum ozlemiae Tuncay & Akalın sp. nov. is described herein based on comprehensive morphological, anatomical, and molecular evidence. The new species is distinguished from its Turkish congeners by white petals with brownish lines (vs. yellow to yellow – green), densely hairy rays and pedicels, shorter pedicels (0.5–2.5 mm), amphisto matic leaves with sparse hairs restricted to upper surface veins, and distinctly unequal mericarps with markedly different wing widths (1.9–3.5 mm vs. 0.5–1 mm). Phylogenetic analyses based on ITS sequences support its placement within Xanthogalum and indicate close affinity with a white – petaled lineage. A detailed morphological description, anatomical characterization, comparisons with related species, an identification key, and a preliminary conservation assessment are provided. Given its extremely restricted distribution and ongoing habitat threats from tourism development, the species is assessed as Endangered (EN) under IUCN criteria.