Pikner, T. 2014 - Evolution, classification and distribution of allotetraploid Dactylorhiza (Orchidaceae) in previously glaciated areas of Europe. Natural. belges 95 (Orchid. 27): 93-114.

Abstract. Pikner, T. 2014 - Evolution, classification and distribution of allotetraploid Dactylorhiza (Orchidaceae) in previously glaciated areas of Europe [Natural. belges 95 (Orchid. 27): 93-114]. Based on several studies provided during the last decade, a review on evolution pattern and distribution of allotetraploid Dactylorhiza taxa in previously glaciated areas of Europe is proposed. Discussed distribution pattern of the allotetraploid Dactylorhiza taxa enables to supplement the preceded hypotheses in a way that the southern and the eastern extent margin of the Weichsel glaciation and extent margin of the WŸrm glaciation during their maximum coincide with the distribution margin of some investigated allotetraploid Dactylorchids. The glaciation extent margin could be characterised as a segregation line between the older taxa and the younger taxa. The hypotheses could be complemented that the younger taxa have evolved in situ and they are distributed mainly in previously glaciated areas while the distribution areas of the older taxa remain mainly outside of the glaciation extent margin. Some older taxa as D. praetermissa and D. majalis have exceeded the extent margin northwards, especially towards Scandinavia. Besides the tendency is, that the younger taxa were exceeded the glaciation extent margin mainly latitudinal, especially eastwards towards western Russian regions. It is hypothesised that D. praetermissa could have a common distribution area from south England through Low Countries further to Jutland during the last glaciation period or earlier, and that the younger taxon of D. traunsteineri could evolve in situ after the melting of the WŸrm ice sheet in Alps and further slightly distributed to the todayĠs habitats in central Europe. Further almost at the same time of a period after the Weischelian and the WŸrm glaciations, among the other allotetraploids the sibling taxa of D. traunsteineri species group were appeared at least in five separated regions, all in formerly glaciated areas: D. traunsteineri in north Tirol, D. curvifolia in north-western Russia, D. lapponica in north Scandinavia, D. russowii in Estonia and D. traunsteinerioides in British and Irish Isles and they should be treated as independent species. The localised allotetraploid post-glacial endemics have evolved far from the glaciation extent margin in the previously glaciated areas and they are restricted with their marginal development niches in coastal areas and islands. It is hypothesised that the localised endemics as D. ebudensis, D. osiliensis, D. baltica var. kuzkenembe, D. vironii, and D. ruthei are the youngest taxa among the investigated allotetraploid taxa.

RŽsumŽ. Pikner, T. 2014 - ƒvolution, classification et distribution de Dactylorhiza allotŽtraplo•des (Orchidaceae) dans les rŽgions auparavant glaciaires de lĠEurope [Natural. belges 95 (Orchid. 27): 93-114]. Sur la base de plusieurs Žtudes effectuŽes ces 10 dernires annŽes, un bilan des caractŽristiques de lĠŽvolution et de la distribution de Dactylorhiza allotetraplo•des dans les rŽgions auparavant glaciaires de lĠEurope est proposŽ. Le schŽma de distribution des Dactylorhiza allotetraplo•des permet de complŽter les hypothses prŽcŽdemment Žmises dans le sens o les limites mŽridionales et orientales de la glaciation de Weichsel et de WŸrm ˆ leur maximum co•ncident avec les limites de la distribution des Dactylorhiza allotŽtraplo•des ŽtudiŽs. Les limites de ces glaciations peuvent tre considŽrŽes comme une ligne sŽparant les taxons les plus jeunes des taxons plus anciens. On peut supposer, de plus, que les taxons plus jeunes ont ŽmergŽ in situ et sont distribuŽs principalement dans les rŽgions auparavant situŽes sous lĠinlandsis alors que la rŽpartition des taxons plus anciens sĠŽtend essentiellement hors des zones auparavant glaciaires. En outre, il semble que les jeunes taxons ont dŽpassŽ les limites de la glaciation principalement en latitude, spŽcialement vers lĠest jusque dans les rŽgions russes occidentales. Il est supposŽ, dĠautre part, que D. praetermissa pourrait avoir eu, durant la dernire glaciation et auparavant, une aire de rŽpartition sĠŽtendant du sud de lĠAngleterre, passant par le Benelux et atteignant le Jutland (Danemark) et que le jeune taxon D. traunsteineri pourrait avoir ŽvoluŽ dans les Alpes aprs la fonte de la calotte glaciaire de WŸrm et avoir ensuite faiblement colonisŽ ses sites actuels en Europe centrale. De plus, presquĠau mme moment, aprs les glaciations de Weichsel et de WŸrm, parmi les autres allotŽtraplo•des, des taxons du groupe de D. traunsteineri sont apparus au moins dans 5 rŽgions sŽparŽes, toutes situŽes dans des zones auparavant glaciaires: D. traunsteineri dans le Tyrol septentrional, D. curvifolia en Russie nord-occidentale, D. lapponica dans le nord de la Scandinavie, D. russowii en Estonie et D. traunsteinerioides dans les ”les Britanniques. Tous ces taxons devraient tre traitŽs comme des espces indŽpendantes. Les allotŽtraplo•des post-glaciaires endŽmiques ont ŽvoluŽ loin des limites de la glaciation et leur distribution est rŽduite ˆ des dŽveloppements marginaux dans des niches de zones c™tires ou dĠ”les. Il est supposŽ que les endŽmiques localisŽs comme D. ebudensis, D. osiliensis, D. baltica var. kuzkenembe, D. vironii et D. ruthei sont les taxons les plus rŽcents parmi les taxons allotŽtraplo•des envisagŽs.

Key-Words. Orchidaceae, Dactylorhiza, polyploidisation, hybridisation, allotetraploid, autotetraploid, diploid, species concept, phylogeny, evolution, distribution, Weichsel glaciation, WŸrm glaciation.