Vol.:(0123456789) 1 3 Plant Systematics and Evolution https://doi.org/10.1007/s00606-019-01622-1 ORIGINAL ARTICLE Genome size variation in the Western Carpathian Sesleria (Poaceae) species Pavol Mereďa Jr. 1  · Monika Majerová 1  · Lajos Somlyay 2  · Ladislav Pekárik 1,3  · Iva Hodálová 1 Received: 12 February 2019 / Accepted: 18 October 2019 © Springer-Verlag GmbH Austria, part of Springer Nature 2019 Abstract The genus Sesleria represents a taxonomically intricate polyploid complex of morphologically highly varied and weakly diferentiated taxa. In the wider area of the Western Carpathians, the genus is represented by three tetraploid (S. caerulea, S. heufleriana, and S. uliginosa) and three octoploid (S. hungarica, S. sadleriana, and S. tatrae) species. Although these taxa play a dominant role in a number of plant communities, their identifcation is often problematic. We examined relative (RGS; 637 individuals, 49 populations) and absolute (AGS; 64 individuals, 19 populations) genome size variation of all six taxa and revealed that genome size could be an efective marker for their identifcation. Genome size allowed not only sepa- ration of the two ploidy levels (4x vs. 8x), but helped to identify at least four of the six studied species. Among tetraploids, RGS appeared to be diagnostic for S. heufleriana (even at individual level), but failed to diferentiate S. caerulea from S. uliginosa. RGS appeared to be diagnostic for octoploid species at population level, although the identity of populations at Vršatec (Slovakia) and Naszály (Hungary) require further studies. We found that octoploid plants from Slavec (Slovakia), formerly identifed as S. heufleriana, actually represent S. hungarica, which is the frst reliable record of this species from Slovakia. In the geographically isolated or peripheral populations, an increased or decreased genome size has been detected. Keywords Carpathians · DNA content · Flow cytometry · Pannonia · Taxonomy Introduction The genome size of angiosperms, as an indicator of ongoing processes of speciation and genetic divergence (e.g. Bennett and Leitch 2005; Leitch and Leitch 2013; Poggio et al. 2014), is considered a notable biological trait in systematic treat- ments. Among others, genome size facilitated delineation of species of taxonomically critical genera such as Lupinus (Fabaceae; Naganowska et al. 2003), Cirsium (Asteraceae; Bureš et al. 2004), Elytrigia (Poaceae; Mahelka et al. 2005), Carthamus (Asteraceae; Garnatje et al. 2006), Fallopia Handling editor: Patrik Mráz. Contribution to “Biogeography of the Carpathians” Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00606-019-01622-1) contains supplementary material, which is available to authorized users. * Pavol Mereďa Jr. pavol.mereda@savba.sk Monika Majerová monika.budzakova@savba.sk Lajos Somlyay somlyay.lajos@nhmus.hu Ladislav Pekárik ladislav.pekarik@savba.sk; ladislav.pekarik@truni.sk Iva Hodálová iva.hodalova@savba.sk 1 Plant Science and Biodiversity Centre, Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, 84523 Bratislava, Slovak Republic 2 Department of Botany, Hungarian Natural History Museum, PO Box 137, 1431 Budapest, Hungary 3 Faculty of Education, Trnava University, Priemyselná 4, PO Box 9, 91843 Trnava, Slovak Republic