AbstractThe genus Crocus is known for its widely varying chromosome numbers (from 2n = 6 to 2n = 70) with varying numbers occurring even within species, as it is the case for Crocus biflorus Miller (2n = 8, 10, 12, 14, 16, 18, 20, 22, 24). After we found morphological diverse C. biflorus populations in Turkey doubts arose about their rank of being subspecies of the Italian C. biflorus (2n = 8). Here we publish the chromosome numbers for 76 populations of C. biflorus sensu lato distributed all over Turkey. The chromosome numbers ranged from 2n = 8 to 2n = 36, with the higher numbers occurring in the mountain ranges of the Anatolian Diagonal and east of it, while lower numbers were found only southwest of these mountains. Closely related taxa with similar distribution mostly differ in their chromosome numbers. This led us to assume that chromosomal changes influence speciation processes in the genus. Therefore, chromosome numbers may represent an important character for the establishment of a new taxonomic treatment of the Crocus species, especially within section Nudiscapus. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)