Heterochromatin and Microevolution in Phleum

A concise history of systematic studies of the genus Phleum L (timothy) is presented. The results of cytotaxonomical studies and their importance for investigation of phylogeny and interrelationships between diploid and polyploid Phleum taxa are discussed. Karyotypes often species belonging to sections Phleum Humphries, Chilochloa (Beauv.) Griseb., and Achnodon Griseb. were studied with conventional and Giemsa C-banding methods and analyzed with regard to nuclear DNA amount. It is suggested that genomic changes in heterochromatin distribution and DNA amount were important factors in the evolution of this genus.