Seven new species and two varieties of Klebsormidium were described using an integrative approach on the base of 28 strains from the poorly studied phylogenetic superclade G. These strains originated from the unusual and exotic habitats (semi-deserts, semi-arid shrublands, Mediterranean shrub and deciduous vegetation, temperate Araucaria forests, peat bogs, dumps after coal mining, maritime sand dunes etc.) of four continents (Africa, South and North America, and Europe). Molecular phylogenies based on ITS-1,2, rbcL gene and concatenated dataset of ITS-1,2-rbcL, secondary structure of ITS-2, morphology, ecology and biogeography, micrographs and drawings of the investigated strains were assessed. Additionally, phylogeny and morphology of 18 Klebsormidium strains from other lineages isolated from the same localities (different vegetation types of Chile and maritime sand dunes of Germany) were investigated for the comparison with representatives of clade G. Clade G Klebsormidium is characterized by distant phylogenetic position from the other Klebsormidium lineages and prominent morphology: four-lobed chloroplasts and mostly short swollen cells in young culture, compact small pyrenoids, curved or disintegrated filaments, unusual elongation of cells in old culture, formation of specific cluster- and knot-like colonies on agar surface, especially prominent in strains isolated from desert regions, from which the group probably originated. Comparison of Klebsormidium diversity from different biogeographic regions showed that the representatives of clade G are common algae in regions of the southern hemisphere (South Africa and Chile) and rare representatives in terrestrial ecosystems of the northern hemisphere. Further investigation of mostly unstudied territories of the southern hemisphere could bring many surprises and discoveries, leading to a change of the present concept that Klebsormidium is cosmopolitan in distribution.

Applied Ecology and Phycology Institute of Biological Sciences University of Rostock Albert Einstein Strasse 3 D 18059 Rostock Germany

Department of Botany Functional Plant Biology University of Innsbruck Sternwartestrasse 15 A 6020 Innsbruck Austria

Institute of Soil Biology Biology Centre of the Czech Academy of Sciences v v i Na Sádkách 7 České Budějovice CZ 37005 Czech Republic

M G Kholodny Institute of Botany National Academy of Sciences of Ukraine Tereschenkivska Str 2 Kyiv 01004 Ukraine

Plant Ecology and Systematics Department of Biology University of Kaiserslautern Erwin Schrödinger Str Bau 13 D 67663 Kaiserslautern Germany

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