Genetic and morphological variation in<i>Viola suavis</i>s.l. (Violaceae) in the western Balkan Peninsula: two endemic subspecies revealed

Abstract

Abstract The Balkan Peninsula, with many endemic species, is known as one of the most important speciation and diversification centres in Europe. Here, we present a study of the western Balkan populations of the polymorphic European species, V. suavis s.l., which have been reported under the name V. adriatica, but their taxonomic status and position within the genus have remained uncertain. Viola suavis s.l. and nine close relatives sampled across Europe were subjected to molecular (sequencing of nuclear ribosomal internal transcribed spacers and amplified fragment length polymorphism), karyological and morphometric analyses. Our results revealed the presence of four allopatric, genetically and morphologically differentiated lineages within V. suavis s.l. in Europe, which are suggested here to be recognized at the subspecific rank. Populations from the western Balkans were segregated into two distinct entities: (1) those from north-western Croatia correspond to the previously recognized taxon, V. suavis subsp. adriatica and (2) those from southern Dalmatia (southern Croatia, southern Bosnia and Herzegovina, and south-western Montenegro) are described here as V. suavis subsp. austrodalmatica subsp. nov. The other two lineages of V. suavis s.l., which both harbour blue- and white-flowered morphotypes, occur in central and eastern Europe (V. suavis subsp. suavis) and in north-eastern Spain (plants provisionally treated as V. suavis 'Spain'). The AFLP and morphological data indicate gene flow between the nominate subspecies and V. suavis subsp. adriatica in a few localities. The distribution of the two western Balkan subspecies is discussed and an identification key to the V. suavis subspecies in Europe is presented. Key words: AFLPflow cytometryITS sequencesmultivariate morphometrics Viola subsect. Viola western Balkans Acknowledgements We thank Karol Marhold (Institute of Botany, Slovak Academy of Sciences, Bratislava, Slovak Republic) for valuable discussions and help during the preparation of the manuscript, Alfred Buchholz (Rottenburg, Germany) for sharing his knowledge of the species V. pyrenaica in the Alps, Vladimir I. Dorofeyev (V. L. Komarov Botanical Institute of the Academy of Sciences of the USSR, St. Petersburg, Russia) for help in finding the lectotype of V. suavis, Jiří Danihelka, Vít Grulich (both Institute of Botany and Zoology, Masaryk University, Brno, Czech Republic), Nejc Jogan (University of Ljubljana, Ljubljana, Slovenia), and Miško Plazibat (University of Zagreb, Zagreb, Croatia) for help with the preparation of the manuscript, Ivan Pišút (Institute of Botany, Slovak Academy of Sciences, Bratislava, Slovak Republic) for correction of the Latin description, and Thomas Marcussen (University of Oslo, Oslo, Norway) for valuable comments on the manuscript. The curators of the BP, BRA, BRNM, BRNU, CL, KRAM, LE, LI, LW, PR, PRC, SAV, SLO, W, WU, ZA and ZAHO herbaria are acknowledged for allowing us to study herbarium specimens. This research was supported by the Slovak Research and Development Agency (grant no. APVV-0368 -07). Associate Editor: Charlie Jarvis