According to Strid, Mountain Flora of Greece (Vol. 1, Cambridge 1986), Dianthus glutinosus (described from the Western Turkish coast), seems to be identical to D. diffusus (earlier described from Attica) and its synonymous name D. pubescens (described from near Athens). This pink is wide spread in Peloponnisos, Sterea Ellas, and the Aegaean islands. Dianthus viscidus (described from Taygetos) is only slightly different, it has more blossoms and different length relations at the calyx. Identical with the latter are D. olympicus (described from Olymbos and Rumelia), D. grisebachii (described from Macedonia), D. parnassicus (from Parnassos), and D. tenuiflorus (from Kavalla and Ueskueb, Skopje). Strid mentions D. tymphresteus as a rather similar species, too. The two latter pinks are growing in higher altitude than D. diffusus.