The article IAPT chromosome data 45 presents the latest collection of chromosome count data of vascular plants gathered through international collaboration under the International Association for Plant Taxonomy (IAPT) patronage. The publication includes karyological studies of more than thirty plant species from various families, primarily from Armenia, Slovakia, the Czech Republic, Poland, and Central Asia. The study reports first or supplementary chromosome counts and newly identified cytotypes for several taxa. The data cover representatives of genera such as Allium, Salvia, Fritillaria, Cardamine, Phragmites, Stipa, Onobrychis, and Ailanthus. These results expand the knowledge of cytogenetic variability in the Eurasian flora and contribute to a better understanding of taxonomic relationships among species.