Four distinct Alnus taxa were recognized using a multidisciplinary approach based on multivariate morphometrics, karyology, flow cytometry and nuclear microsatellite analyses. Besides the long-recognized diploid taxa (2n = 2x = 28) A. glutinosa and A. incana, we revealed the presence of morphologically, cytologically and genetically noticeably delimited tetraploid populations (2n = 4x = 56), which we consider new species. These form two geographically well delimited clusters located in the Iberian Peninsula and the adjacent part of North Africa, designated here as Alnus lusitanica, and in the Dinaric Alps extending south-easterly to Greece, denominated here as Alnus rohlenae.
Vít P., Douda J., Krak K., Havrdová A. & Mandák B. (2017): Two new tree polyploid species closely related to Alnus glutinosa in Europe and North Africa – an analyses based on morphometry, karyology, flow cytometry and microsatellites. Taxon, in press.
Mandák B., Vít P., Krak K., Trávníček P., Drašnarová A., Hadincová V., Zákravský P., Jarolímová V., Bacles C.F.E. & Douda J. (2016): Flow cytometry, microsatellites and niche models reveal the origins and geographic structure of Alnus glutinosa populations in Europe. Annals of Botany 117: 107–120.