Distribution, taxonomy, nomenclature and molecular genetic data are presented for two closely related pairs of birch taxa: (1) dark-barked Betula pubescens var. sibakademica (Baran.) Kuzeneva (basionym B. sibakademica Baranov) and white-barked B. pubescens var. pubescens, and (2) dark-barked B. kotulae Zaverucha = B. pendula var. obscura (Kotula ex Fiek) Olšavská (basionym B. obscura Kotula ex Fiek, heterotypic synonym B. kotulae) and white-barked B. pendula, respectively. Using published data and sequences obtained in this study, it was found that, although these pairs can be distinguished not only by morphological characters but also by two diagnostic single nucleotide polymorphisms (SNPs) in the internal transcribed spacers ITS1 and ITS2, no sequence differences within each pair were detected. These results suggest that the colour of the bark cannot be used as a taxonomic trait at the species level, and the dark-barked birches within each pair should not be treated as separate species or varieties, but as forms, respectively. Therefore, we reassessed the taxonomic status of B. sibakademica and B. kotulae using morphological traits and molecular genetic markers and suggest that B. pubescens f. sibakademica (Baranov) Tarieiev comb. nov. and B. pendula f. obscura (Kotula ex Fiek) Tarieiev comb. nov. should be used for them, respectively. Betula pubescens f. sibakademica was described in Ukraine for the first time.

The present study is focused on several species from the genus Astragalus L. with the aim to clarify the taxonomic status of Ukrainian local endemic species Astragalus borysthenicus Klokov, which is sometimes considered a synonym to A. onobrychis L. In this study, the morphological features, current taxonomy, taxonomical history, and phylogenetic analysis based on rDNA Bayesian inference, as well as comparative analysis of ITS1 and ITS2 secondary structures, were investigated. It was found that A. borysthenicus is distant from A. onobrychis according to phylogenetic analysis. Moreover, A. borysthenicus has differences from the investigated taxa in its secondary structures of ITS1 and ITS2 transcripts. These data suggest that A. borysthenicus should be treated as a separate species rather than a synonym to A. onobrychis.

The DNA isolation CTAB-method modified for seed plants herbarium material is proposed. Three modifications were tested on 29 samples from KW and KWU herbaria. Visual evaluation of optimal method is done for DNA containing pellet, PCR products (nuclear ITS and plastid rbcL gene sequence), amplicon sequencing with further comparing results obtained using those deposited in GenBank. The optimal variant of DNA extraction from herbarium material for different taxonomical groups of plants is proposed.

The article provides data about authentic materials of Betula (Betulaceae) names described from Ukraine and deposited at the National Herbarium of Ukraine (KW). For each taxon, its protologue, synonyms and text of the label are presented. We designate here lectotypes of Betula borysthenica Klokov, B. klokovii Zaverucha, and report the holotype of B. kotulae Zaverucha, and authentic materials of B. klokovii Zaverucha, B. polessica Ivchenko etc.

Until recently, Festuca arietina was practically an unknown species in the flora of Eastern Europe. Such a situation can be treated as a consequence of insufficient studying of Festuca valesiaca group species in Eastern Europe and misinterpretation of the volume of some taxa. As a result of a complex study of F. arietina populations from the territory of Ukraine (including the material from locus classicus), Belarus and Lithuania, original anatomy, morphology and molecular data were obtained. These data confirmed the taxonomical status of F. arietina as a separate species. Eleven morphological and 12 anatomical characters, ITS1-5.8S-ITS2 cluster of nuclear ribosomal genes, as well as the models of secondary structure of ITS1 and ITS2 transcripts were studied in this approach. It was found for the first time that F. arietina is hexaploid (6x = 42), which is distinguished from all the other narrow-leaved fescues by specific leaf anatomy as well as in ITS1-5.8S-ITS2 sequences. Molecular data indicating possible hybridogenous origin of F. arietina, fall in line with the anatomical-morphological data and explain the tendency toward sclerenchyma strands fusion with formation of a continuous ring in F. arietina, as well as F. arietina ecological confinement to psammophyte biotopes.