Hesperis turkmendaghensis A.Duran & A.Ocak sp. nov. (Cruciferae) is described and illustrated from Anatolia, Turkey. The species grows under mixed forest, open forest and shady slopes in Turkmen Dagi (B3 Eskisehir) in Central Anatolia. It is closely related to H. matronalis L. ssp. matronalis, an endemic confined to Central Anatolia. Diagnostic morphological characters are discussed. Notes are also presented on its ecology, biogeography and conservation status. In addition, the pollen characteristics and seed coat surface of H. turkmendaghensis and H. matronalis are examined by SEM. (C) 2005 The Linnean Society of London, Botanical Journal of the Linnean Society.