Abstract
This article presents the results of a comprehensive study of the species composition of the Poaceae Barnhart family in the flora of the Betpakdala Desert. The research is based on a critical review of published literature, examination of herbarium specimens from collections housed at AA and MW, and extensive fieldwork conducted by the authors. As a result, an updated checklist of Poaceae taxa for the region has been compiled. It includes 106 species distributed across 44 genera, 17 subtribes, 14 tribes, 7 supertribes, and 6 subfamilies. The taxonomic arrangement follows the contemporary classification system adopted by the Angiosperm Phylogeny Group IV (APG IV), and species names are aligned with the nomenclature recognized in the Plants of the World Online (POWO) database. For each species, the checklist provides detailed information on its taxonomic placement, latin binomial with author citation, life form, ecological grouping based on water availability and substrate type, habitat conditions, and flowering period. The genera with the highest species richness in the region are Stipa L. (11 species), Puccinellia Parl. (9), Poa L. (8), Bromus L. (8), and Leymus Hochst. (7). The article also includes a comparative analysis of the Poaceae species composition of Betpakdala with adjacent regions, including the Central Kazakh Upland, the Ulytau Mountains, and the Moyinkum Desert. Using the Sørensen similarity coefficient, it was determined that the highest floristic similarity exists between Betpakdala and Moyinkum, with a similarity index of 0.7. These findings contribute to a deeper understanding of grass diversity in Central Kazakhstan’s arid ecosystems.