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The present distribution of Siberian boreal forests that are dominated by larches (Larix spp.) is influenced, to an unknown extent, by glacial history. Knowing the past treeline dynamics can improve our understanding of future treeline shifts under changing climate. Here, we study patterns in the genetic variability of Siberian Larix to help unravel biogeographic migration routes since the Last Glacial Maximum (LGM). We infer the spatial distribution and the postglacial demographic history of Larix using genome‐wide single nucleotide polymorphisms (SNPs) derived through genotyping by sequencing (GBS) from 130 individuals sampled across eastern Siberia. Our analysis gives statistical support for two or three clusters, spanning from western to eastern Siberia. These clusters reveal a genetic structure influenced by isolation resulting from geographical distance, barriers imposed by geographic features, and distinct glacial histories. Assuming three clusters, our demographic inference indicates that the common ancestor of the current Larix populations existed in northeast Siberia well before the LGM. This suggests that Larix persisted in the northern region throughout previous glacials. Our genetic studies suggest that Larix likely survived the cold LGM in northern refugia, enabling a fast colonization of Siberia. Instead of complete repopulation from southern areas postglacially, the northernmost Larix expansion during the Holocene seems to have benefitted from refugial populations ahead of the treeline. Present‐day migration is expected to be slow initially, due to the absence of current refugial populations in the far north, in contrast to the early‐Holocene situation. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates that wide distributed bryophyte taxa with homogeneous morphology may represent separate evolutionary lineages. The evolutionary histories of these cryptic lineages may be related to historical factors, such as the climatic oscillations in the Quaternary. Thus, the post-glacial demographic signatures paired with cryptic speciation may result in complex phylogeographic patterns. This research has two aims: to determine whether the widespread moss Racomitrium lanuginosum represents cryptic molecular taxa across the Northern Hemisphere and to infer the effects of Quaternary glaciations on spatial genetic diversity. We used the internal transcribed spacer (ITS) marker to resolve the phylogeographic history of the species and single nucleotide polymorphisms (genotyping-by-sequencing) to infer the genetic structure and demographic history. Finally, we assessed the historical changes in the distribution range using species distribution models. Racomitrium lanuginosum comprises distinct molecular lineages sympatrically distributed in the Northern Hemisphere. We also uncovered long-distance dispersal from eastern North America to Scandinavia and potential in situ survival in northern Scandinavia. Due to the genetic signatures, the Alaska Peninsula could be considered a glacial refugium. The species experienced post-glacial expansion northwards in the Northern Hemisphere, mainly from the Alaska Peninsula. Our results exemplify the complex phylogeographic history in cold environments and contribute to recognizing evolutionary patterns in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

A Crocus population in the Northern Albanian Alps obviously belonging to C. ser. Verni was referred to C. heuffelianus, but closer field investigations revealed that it could not be identified with this or any other Verni species. The detailed description of a new species, Crocus bertiscensis, including morphology, leaf anatomy, cytology, and phylogenetic relationship is provided and illustrated. Phylogenetic analyses based on genome-wide single nucleotide polymorphism data obtained through genotyping-by-sequencing placed C. bertiscensis as clearly distinct from C. heuffelianus, supporting its rank as a species within C. ser. Verni. Morphologically, it differs from C. heuffelianus by showing paler and flatter perigone segments, short perigone tubes and leaf white stripe width of 1/7 compared to the leaf diameter. Finally, karyological and molecular analysis revealed that C. bertiscensis applies to the 2n = 12 cytotype of C. heuffelianus from Čakor Pass area reported by earlier studies. [ABSTRACT FROM AUTHOR]

Phylogenetic relationships among the taxa of Crocus series Crocus are still unclear, preventing the understanding of species diversity and the evolution of the important spice saffron ( Crocus sativus ). Therefore, we analyzed sequences of two chloroplast ( trn L- trn F, mat K- trn K) and three nuclear (TOPO6, ribosomal DNA ETS and ITS) marker regions to infer phylogenetic relationships among all species belonging to series Crocus . Our phylogenetic analyses resolved the relationships among all taxa of the series. Crocus hadriaticus and the former C. pallasii subspecies appeared polyphyletic. The latter deserve elevating the subspecies to species rank, while for C. hadriaticus a detailed study of species boundaries is necessary. Multi-locus and also genome-wide single nucleotide polymorphism data obtained through genotyping-by-sequencing placed C. sativus within C. cartwrightianus with no indication that other Crocus species contributed to the evolution of the triploid. Our analyses thus made an autotriploid origin of C. sativus from C. cartwrightianus very likely. [ABSTRACT FROM AUTHOR]