Oenothera rosea (Onagraceae): a newly naturalized alien plant species in Turkiye

Oenothera rosea (Onagraceae), native to central and southern Texas (USA), Mexico, Central America to El Salvador, and much of South America, was encountered within the Avşar campus of Kahramanmaraş Sütçü İmam University, located in Kahramanmaraş Province, southern Türkiye.The species was discovered serendipitously and was observed to be well established in two adjacent grassy areas, with two independently reproducing subpopulations totaling at least 250 individuals.Although the exact pathway of introduction remains uncertain, it is likely that O. rosea arrived unintentionally, possibly as a contaminant in soil or accompanying ornamental plants introduced for landscaping purposes.This perennial species, typically inhabiting temperate biomes, is also known for its medicinal uses.With the inclusion of O. rosea, the total number of Oenothera species documented in Türkiye now stands at five.The species is readily distinguishable from its congeners by its small petals and characteristic pink corolla.Key taxonomic features include: short stems (15-35 cm), either simple or branched, strigillose (sometimes mixed villous hairs); pink petals measuring 4-8 mm; floral tubes 3-5 mm; clavate to narrowly obovoid capsules (4-10 × 2-5 mm), angled or slightly winged valves; and a sterile stipe (pedicel) of 5-20 mm.A detailed botanical description, habitat characteristics, field photographs, and a distribution map are provided.Additionally, the identification key for the genus Oenothera in Türkiye has been updated to reflect this new record.