Centaurea tomarzaensis and Centaurea yozgatensis subsp. vulcanica, two new Centaurea (sect. Centaurea, Asteraceae) taxa from Turkey

This paper presents two new cornflowers with small heads, identified based on morphology, karyology, and molecular comparisons. The first taxon, Centaurea tomarzaensis, is similar morphologically to Centaurea pinetorum, however, it has been distinguished based on differences in its basal leaves, phyllaries, and appendages, as well as its fruit features. The second taxon is closely related to Centaurea yozgatensis, represented by a population distributed in a narrow area at low altitudes on the western side of the Sakarya Valley (Province of Bilecik). A new and distinct population was discovered within the borders of Kargı Dam (Province of Beypazarı/Ankara), located on volcanic tuff rocks at the easternmost part of the valley. This population differs from the typical form in terms of its numerous branched stems and capitula, as well as its hairy appearance. It has thus been determined as a new subspecies, Centaurea yozgatensis subsp. vulcanica. A distribution map and identification key for the taxa are also provided.