Chromosome number, karyotype and pollen morphology of the rare endemic Centaurea goeksunensis

In this paper, chromosome number, karyotype and pollen morphology of Centaurea goeksunensis Aytaç & H. Duman, described in 2005, are studied for the first time. Centaurea goeksunensis is found to be tetraploid (2n=4x=60). This is the second record of polyploidy in Centaurea sect. Psephelloideae (Boiss.) Sons. The basic chromosome number of C. goeksunensis was found to be x=15 and the haploid karyotype formula is 18 m+10 sm+2 st. The pollen grains of C. goeksunensis were found to be radially symmetric, isopolar and tricolporate. They are intersemiangular in polar view and prolate–sphaeroidal in equatorial view. The exine is thickened at the poles.