Diversity of the genus Genkalia (Bacillariophyta) in boreal and mountain lakes - taxonomy, distribution and ecology.

Genkalia digitulus (HUSTEDT) LANGE-BERT. et KULIKOVSKIY (equivalent to Navicula digitulus HUSTEDT) is recorded from several lakes in the northern Europe and from high altitude lakes all over Europe. Wide distribution and characteristic autecology of this species allow its use as a bioindicator of pH changes and reliable marker of environmental reconstruction. A comparison of specimens found in lakes from the Carpathian and Balkan Mountains with the type material of Genkalia digitulus (HUSTEDT) LANGE-BERT. et KULIKOVSKIY resulted in description of a new species -G. boreoalpina WOJTAL, C.E. WETZEL, ECTOR, OGNJANOVA-RUMENOVA et BUCZKO. Genkalia boreoalpina is characterised by valve outline, size and parallel striae throughout most of the valve. The separation was based on light and scanning electron microscopy. Genkalia boreoalpina was the most common diatom of the genus from high mountain lakes of slightly acidic waters with a very low mineral content. The third species, Navicula subprocera Hustedt, was found in the Lake Calcescu (Parang Mountains) in alkaline waters and in a mountain fen in Herzegovina. The nomenclatorial combination to Genkalia was made for this species. Previously published data suggest there is a much larger diversity of species in the genus Genkalia and the cosmopolitan distribution of this group is mostly presented at the genus level.